FORGE-PRACTICE 

AND 

HEAT  TREATMENT  OF  STEEL 


BY 

JOHN    LORD    BACON 

Construction  Engineer 

Member  American  Society  of  Mechanical  Engineers 

Sometime  Instructor  in  Forge  Practice  and  Machine  Design, 

Lewis  Institute,  Chicago 


THIRD  EDITION,  REVISED  AND  ENLARGED 
BY 

EDWARD  R.  MARKHAM 

Consulting  Engineer 
Specializing  in  Heat  Treatment  of  Steel 


NEW  YORK: 

JOHN  WILEY  &  SONS,  INC. 

LONDON:  CHAPMAN  &  HALL,  LIMITED 

1919 


Copyright,  1904,  1908,  1919. 

BY 
JOHN  L.  BACON 


PRESS  OF 

BRAUNWORTH   &  CO. 

PRINTERS    AND    BOOKBINDERS 

BROOKLYN,    N.    Y. 


Co  mj)  SSlffe, 

WITHOUT  WHOSE   ASSISTANCE   IT  WOULD 

NEVER     HAVE     BEEN     WRITTEN, 

THIS  LITTLE  VOLUME  IS 

DEDICATED. 


PREFACE    TO   THE    THIRD    EDITION. 


MODERN  demands  on  the  finished  products  of 
steel  have  necessitated  rapid  strides  in  the  art  of 
heat  treatment  of  the  metal.  As  the  subjects  of 
forging,  hardening,  tempering  and  annealing  are  so 
closely  correlated  it  has  seemed  wise  to  add  to 
"Forge  Practice"  a  certain  amount  of  material 
devoted  to  the  other  branches  of  the  art. 

The  introduction  of  heat  measuring  and  hardness 
testing  instruments,  together  with  various  other 
modern  appliances,  and  up  to  date  systems  of  doing 
work  have  made  necessary  a  broader  knowledge  of 
heat-treating  methods  than  was  formerly  the  case: 
for  after  all  the  most  important  factor  is  the  man 
doing  the  work. 

It  is  the  earnest  wish  of  the  writers  of  this  volume 
that  it  may  be  instrumental  in  helping  men  engaged 
in  heat  treating  steel  to  be  of  greater  value  to  them- 
selves and  others. 


PREFACE  TO   THE   SECOND  EDITION. 


THE  author  believes  that  the  text  book  should 
be  used  to  explain  principles  and  give  examples, 
not  to  give  minute  explicit  directions  for  making 
a  set  of  exercises. 

This  necesitates  an  independent  set  of  drawings 
for  the  work  to  be  done. 

It  is  for  this  purpose  that  the  set  of  drawings 
is  given. 

The  author  has  felt  the  need  and  lack  of  such 
drawings  in  the  text-book  as  used  before,  and  it  is 
to  remedy  this  defect  that  the  addition  has  been 
made. 

The  exercises  are  such  as  have  been  found  useful 
in  the  shop,  and  an  effort  has  also  been  made 
to  give  drawings  of  such  tools  as  are  ordinarily 
used  in  the  forge  and  machine  shops. 

J.  L.  B. 

March,  1908. 

vi 


PREFACE   TO  THE   FIRST   EDITION. 


THIS  little  volume  is  the  outgrowth  of  a  series  of 
notes  given  to  the  students  at  Lewis  Institute  from  time 
to  time  in  connection  with  shop  work  of  the  character 
described. 

It  is  not  the  author's  purpose  to  attempt  to  put  forth 
anything  which  will  in  any  way  take  the  place  of  actual 
shop  work,  but  rather  to  give  some  explanation  which  will 
aid  in  the  production  of  work  in  an  intelligent  manner. 

The  examples  cited  are  not  necessarily  given  in  the 
order  in  which  they  could  most  advantageously  be  made 
as  a  series  of  exercises,  but  are  grouped  under  general 
headings  in  such  a  way  as  to  be  more  convenient  for 
reference. 

The  original  drawings  from  which  the  engravings 
were  made  were  drawn  by  L.  S.  B. 


CONTENTS. 


CHAPTER  I 

PAGB 

GENERAL  DESCRIPTION  OF  FORGE  AND  TOOLS i 


CHAPTER  II. 
WELDING  ...................................................     17 

CHAPTER  III. 
CALCULATION  or  STOCK  FOR  BENT  SHAPES  ....................     41 

CHAPTER  IV 
UPSETTING,  DRAWING  OUT,  AND  BENDING  ....................         *i 


CHAPTER  V. 
SIMPLE  FORGED  WORK  .......................................     68 

CHAPTER  VI. 
CALCULATION  OF  STOCK;  AND  MAKING  OF  GENERAL  FORCINGS.  ...     90 

CHAPTER  VII. 
STEAM-HAMMER  WORK  .......................  ..,..'.  ..........   120 

CHAPTER  VIII. 
DUPLICATE  WORK  ..............................  .  ............   146 

ix 


CONTENTS 


CHAPTER  IX. 

PAGE 

TOOL  FORGING  AND  TEMPERING 159 


CHAPTER  X. 

MISCELLANEOUS  WORK 183 

TABLES ; 377 

COURSE  OF  EXERCISES  IN  FORGE  WORK , 387 

INDEX 409 


FORGE-PRACTICE. 


CHAPTER  I. 

GENERAL  DESCRIPTION   OF  FORGE  AND  TOOLS. 

Forge. — The  principal  part  of  the  forge  as  gener- 
ally made  now  is  simply  a  cast-iron  hearth  with 
a  bowl,  or  depression,  in  the  center  for  the  fire. 
In  the  bottom  of  this  bowl  is  an  opening  through 
which  the  blast  is  forced.  This  blast-opening 
is  known  as  the  tuyere.  Tuyeres  are  made  in 
various  shapes;  but  the  object  is  the  same  in  all, 
that  is,  to  provide  an  opening,  or  a  number  of 
openings,  of  such  a  shape  as  to  easily  allow  the 
blast  to  pass  through,  and  at  the  same  time,  as 
much  as  possible,  to  prevent  -the  cinders  from 
dropping  into  the  blast-pipe. 

There  should  be  some  means  of  opening  the 
blast-pipe  beneath  the  tuyere  and  cleaning  out 
the  cinders  which  work  through  the  tuyere-open- 
ings, as  some  cinders  are  bound  to  do  this  no 
matter  how  carefully  the  tuyere  is  designed. 

When  a  long  fire  is  wanted,  sometimes  several 


2    :  ^\  :  ^ ••*  ;•  t^ t  i ..  *'   '  J      .  ,^Qfta,E-  PRACTICE. 

tuyeres  are  placed  in  a  line;  and  for  some  special 
work  the  tuyeres  take  the  form  of  nozzles  pro- 
jecting inwardly  from  the  side  of  the  forge. 

Coal. — The  coal  used  for  forge-work  should  be 
of  the  best  quality  bituminous,  or  soft,  coal.  It 
should  coke  easily;  that  is,  when  dampened  and 
put  on  the  fire  it  should  cake  up,  form  coke,  and 
not  break  into  small  pieces.  It  should  be  as  free 
from  sulphur  as  possible,  and  make  very  little 
clinker  when  burned. 

Good  forge-coal  should  be  of  even  structure 
through  the  lumps,  and  the  lumps  should  crumble 
easily  in  the  hand.  The  lumps  should  crumble 
rather  than  split  up  into  layers,  and  the  broken 
pieces  should  look  bright  and  glossy  on  all  faces, 
almost  like  black  glass,  and  show  no  dull-looking 
streaks. 

Ordinary  soft  coal,  such  as  is  used  for  "  steam- 
ing-coal,"  makes  a  dirty  fire  with  much  clinker. 
"  Steaming-coal "  when  broken  is  liable  to  split 
into  layers,  some  of  which  are  bright  and  glossy, 
while  others  are  dull  and  slaty-looking. 

Fire. — On  the  fire,  to  a  very  great  extent,  depends 
the  success  or  failure  of  all  forging  operations, 
particularly  work  with  tool-steel  and  welding. 

In  building  a  new  fire  the  ashes,  cinders,  etc., 
should  be  cleaned  away  from  the  center  of  the 
forge  down  to  the  tuyere.  Do  not  clean  out  the 
whole  top  of  the  forge,  but  only  the  part  where 
the  new  fire  is  wanted,  leaving,  after  the  old 
material  has  been  taken  out,  a  clean  hole  in  which 
to  start  the  fresh  fire. 


GENERAL    DESCRIPTION   OF    FORGE    AND    TOOLS.  3 

The  hearth  of  the  forge  is  generally  kept  filled 
with  cinders,  etc.,  even  with  the  top  of  the  rim. 

Shavings,  oily  waste,  or  some  other  easily  lighted 
material  should  be  placed  on  top  of  the  tuyere 
and  set  on  fire. 

As  soon  as  the  shavings  are  well  lighted,  the 
blast  should  be  turned  on  and  coke  (more  or  less 
of  which  is  always  left  over  from  the  last  fire) 
put  on  top  and  outside  of  the  burning  shavings. 
Over  this  the  " green  coal"  should  be  spread. 

Green  coal  is  fresh  coal  dampened  with  water. 
Before  using  the  forge-coal  it  should  be  broken 
into  small  pieces  and  thoroughly  wet  with  water. 
This  is  necessary,  as  it  holds  together  better  when 
coking,  making  better  coke  and  keeping  in  the 
heat  of  the  fire  better.  It  is  also  easier  to  prevent 
the  fire  from  spreading  out  too  much,  as  this 
dampened  coal  can  be  packed  down  hard  around 
the  edges,  keeping  the  blast  from  blowing  through. 

The  fire  should  not  be  used  until  all  the  coal  on 
top  has  been  coked.  As  the  fire  burns  out  in  the 
center,  the  coke,  which  has  been  forming  around 
the  edge,  is  pushed  into  the  middle,  and  more 
green  coal  added  around  the  outside. 

We  might  say  the  fire  is  made  up  of  three  parts: 
the  center  where  the  coke  is  forming  and  the  iron 
heating;  a  ring  around  and  next  to  this  center 
where  coke  is  forming;  and,  outside  of  this,  a  ring 
of  green  coal. 

This  is  the  ordinary  method  of  making  a  small 
fire. 

This  sort  of  fire  is  suitable  for  smaller  kinds  of 


4  FORGE-PRACTICE. 

work.  It  can  be  used  for  about  an  hour  or  two, 
at  the  end  of  which  time  it  should  be  cleaned. 
When  welding,  the  cleaning  should  be  done  much 
oftener. 

Large  Fires. — Larger  fires  are  sometimes  made 
as  follows :  Enough  coke  is  first  made  to  last  for 
several  hours  by  mounding  up  green  coal  over 
the  newly  started  fire  and  letting  it  burn  slowly 
to  coke  thoroughly.  This  coke  is  then  shoveled 
to  one  side  and  the  fire  again  started  in  the  follow- 
ing way:  A  large  block,  the  size  of  the  intended 
fire,  is  placed  on  top  of  the  tuyere  and  green  coal 
is  packed  down  hard  on  each  side,  forming  two 
mounds  of  closely  packed  coal.  The  block  is 
taken  out  and  the  fire  started  in  the  hole  between 
the  two  mounds,  coke  being  added  as  necessary. 
This  sort  of  a  fire  is  sometimes  called  a  stock  fire, 
and  will  last  for  some  time.  The  mounds  keep 
the  fire  together  and  help  to  hold  in  the  heat. 

For  larger  work,  or  where  a  great  many  pieces 
are  to  be  heated  at  once,  or  when  a  very  even 
or  long-continued  heat  is  wanted,  a  furnace  is 
used.  For  furnace  use,  and  often  for  large  forge- 
fires,  the  coke  is  bought  ready-made. 

Banking  Fires.  -  -  When  a  forge -fire  is  left  it 
should  always  be  banked.  The  coke  should  be 
well  raked  up  together  into  a  mound  and  then 
covered  with  green  coal.  This  will  keep  the  fire 
alive  for  some  time  and  insure  plenty  of  good 
coke  for  starting  anew  when  it  does  die  out.  A 
still  better  method  to  follow,  when  it  is  desired 
to  keep  the  fire  for  some  time,  is  to  bury  a  block 


GENERAL   DESCRIPTION   OF    FORGE    AND    TOOLS.  5 

of  wood  in  the  center  of  the  fire  when  bank- 
ing it. 

Oxidizing  Fire.  —  When  the  blast  is  supplied 
from  a  power  fan,  or  blower,  the  beginner  generally 
tries  to  use  too  much  air  and  blow  the  fire  too  hard. 

Coal  requires  a  certain  amount  of  air  to  burn 
properly,  and  as  it  burns  it  consumes  the  oxygen 
from  the  air.  When  too  much  blast  is  used  the 
oxygen  is  not  all  burned  out  of  the  air  and  will 
affect  the  heated  iron  in  the  fire.  Whenever  a 
piece  of  hot  iron  comes  in  contact  with  the  air  the 
oxygen  of  the  air  attacks  the  iron  and  forms  oxide. 
This  oxide  is  the  scale  which  is  seen  on  the  outside 
of  iron.  The  higher  the  temperature  to  which  the 
iron  is  heated,  the  more  easily  the  oxide  is  formed. 
When  welding,  particularly,  there  should  be  as 
little  scale,  or  oxide,  as  possible,  and  to  prevent  its 
formation  the  iron  should  not  be  heated  in  con- 
tact with  any  more  air  than  necessary.  Even  on 
an  ordinary  forging  this  scale  is  a  disadvantage, 
to  say  the  least,  as  it  must  be  cleaned  oJ,  and 
even  then  is  liable  to  leave  the  surface  of  the  work 
pitted  and  rough.  If  it  were  possible  to  keep  air 
away  from  the  iron  entirely,  no  trace  of  scale  would 
be  formed,  even  at  a  high  heat. 

If  just  enough  air  is  blown  into  the  fire  to  make 
it  burn  properly,  all  the  oxygen  will  be  burned 
out,  and  very  little,  if  any,  scale  will  be  formed 
while  heating.  On  the  other  hand,  if  too  much 
air  is  used,  the  oxygen  will  not  all  be  consumed 
and  this  unburned  oxygen  will  attack  the  iron 
and  form  scale.  This  is  known  as  ''oxidizing"; 


0  FORGE-PRACTICE. 

that  is,  when  too  much  air  is  admitted  to  the  fire 
the  surplus  oxygen  will  attack  the  iron,  forming 
"oxide,"  or  scale.  This  sort  of  a  fire  is  known  as 
an  " oxidizing"  fire  and  has  a  tendency  to  "  oxidize" 
anything  heated  in  it. 

Anvil. — The  ordinary  anvil,  Fig.  i,  has  a  body 
of  cast  iron,  wrought  iron,  or  soft  steel,  with  a 
tool-steel  face  welded  on  and  hardened.  The 
hardened  steel  covers  jusf  the  top  face,  leaving 
the  horn  and  the  small  block  next  the  horn  of  the 
softer  material. 


FIG.  i. 

The  anvil  should  be  so  placed  that  as  the  work- 
man faces  it  the  horn  will  point  toward  his  left. 

The  square  hardie-hole  in  the  right-hand  end  of 
the  face  is  to  receive  and  hold  the  stems  of  hardies, 
swages,  etc. 

For  small  work  the  anvil  should  weigh  about 
150  Ibs. 

Hot  and  Cold  Chisels. — Two  kinds  of  chisels  are 
commonly  used  in  the  forge-shop:  one  for  cutting 


GENERAL    DESCRIPTION    OF    FORGE   AND    TOOLS.  7 

cold  stock,  and  the  other  for  cutting  red-hot  metal. 
These  are  called  cold  and  hot  chisels. 

The  cold  chisel  is  generally  made  a  little  thicker 
in  the  blade  than  the  hot  chisel,  which  is  forged 
down  to  a  thin  edge. 

.  Fig.  2  shows  common  shapes  for  cold  and  hot 
chisels,  as  well  as  a  hardie,  another  tool  used  for 
cutting. 


HARDIE 


FlG.   2. 

Both  chisels  should  be  tempered  alike  when 
made. 

The  cold  chisel  holds  its  temper ;  but,  from  con- 
tact with  hot  metal,  the  hot  chisel  soon  has  its 
edge  softened.  For  these  reasons  the  two  chisels 
should  never  be  used  in  place  of  each  other,  for  by 
using  the  cold  chisel  on  hot  work  the  temper  is 
drawn  and  the  edge  left  too  soft  for  cutting  cold 
metal,  while  the  hot  chisel  soon  becomes  so  soft 
that  if  used  in  place  of  the  cold  it  will  have  its 
edge  turned  and  ruined. 

It  would  seem  that  it  is  useless  to  temper  a  hot 
chisel,  as  the  heated  work,  with  which  the  chisel 


8  FORGE- PRACTICE. 

comes  in  contact,  so  soon  draws  the  temper.  When 
the  chisel  is  tempered,  however,  the  steel  is  left  in 
a  much  better  condition  even  after  being  affected 
by  hot  metal  on  which  it  is  used  than  it  would 
be  if  the  chisel  were  made  untempered. 

Grinding  Chisels. — It  is  very  important  to  have 
the  chisels,  particularly  cold  chisels,  ground  cor- 
rectly, and  the  following  directions  should  be 
carefully  followed. 

The  sides  of  a  cold  chisel  should  be  ground  to 
form  an  angle  of  about  60°  with  ^ach  other,  as 
shown  in  Fig.  3.  This  makes  an  angle  blunt 


FIG.  3. 

enough  to  wear  well,   and  also   sharp   enough  to 
cut  well. 

The  cutting  edge  should  be  ground  convex, 
or  curving  outward,  as  at  B.  This  prevents  the 
corners  from  breaking  off.  When  the  edge  of  the 
chisel  is  in  this  shape,  the  strain  of  cutting  tends 
to  force  the  corners  back  against  the  solid  metal 


GENERAL   DESCRIPTION    OF   FORGE   AND    TOOLS.  9 

in  the  central  part  of  the  tool.  If  the  edge  were 
made  concave,  like  C,  the  strain  would  tend  to 
force  the  corners  outward  and  snap  them  off.  The 
arrows  on  B  and  C  indicate  the  direction  of  these 
forces. 

Hot  chisels  should  be  ground  sharper.  The 
sides  should  be  ground  at  an  angle  of  about  30° 
instead  of  60°. 

Another  tool  used  for  cutting  is  the  hardie.  This 
takes  the  place  of  the  cold  or  hot  chisel.  It  has  a 
stem  fitted  to  the  square  hole  in  the  right-hand  end 
of  the  anvil  face,  this  stem  holding  the  hardie  in 
place  when  in  use. 

Cutting  Stock. — When  soft  steel  and  wrought-iron 
bars  are  cut  with  a  cold  chisel  the  method  should 
be  about  as  follows:  First  cut  about  one-fourth 
of  the  way  through  the  bar  on  one  side;  then 
make  a  cut  across  each  edge  at  the  ends  of  the 
first  cut;  turn  the  bar  over  and  cut  across  the 
second  side  about  one-fourth  the  way  through; 
tilt  the  bar  slightly,  with  the  cut  resting  on  the 
outside  corner  of  the  anvil,  and  by  striking  a  sharp 
blow  with  the  sledge  on  the  projecting  end,  the 
piece  can  generally  be  easily  broken  off. 

Chisels  should  always  be  kept  carefully  ground 
and  sharp. 

A  much  easier  way  of  cutting  stock  is  to  use 
bar  shears,  but  these  are  not  always  at  hand. 

The  edge  of  a  chisel  should  never  under  any  circum- 
stances be  driven  clear  through  the  stock  and  allowed 
to  come  in  contact  with  the  hard  face  of  the  anvil. 

Sometimes  when  trimming  thin  stock  it  is  con- 


I O  FORGE-PRACTICE. 

venient  to  cut  clear  through  the  piece;  in  this 
case  the  cutting  should  be  done  either  on  the  horn, 
the  soft  blcck  next  the  horn,  or  the  stock  to  be 
cut  should  be  backed  up  with  some  soft  metal. 
An  easy  way  to  do  this  is  to  cut  a  wide  strip  of 
stock  about  two  inches  longer  than  the  width  of 
the  face  of  the  anvil,  and  bend  the  ends  down  to 
fit  over  the  sides  of  the  anvil.  The  cutting  may 
be  done  on  this  without  injury  to  the  edge  of  the 
chisel.  It  is  very  convenient  to  have  one  of  these 
strips  always  at  hand  for  use  when  trimming  thin 
work  with  a  hot  chisel. 

The  author  has  seen  a  copper  block  used  for 
this  same  purpose.  The  block 
was  formed  like  Fig.  4,  the  stem 
being  shaped  to  fit  into  the  hardic- 
hole  of  the  anvil.  This  block  was 
designed  for  use  principally  when 
FIG.  4.  trimming  thin  parts  of  heated 

work  with  a  hot   chisel. 

Care  should  always  be  taken  to  see  that  the 
work  rests  flat  on  the  anvil  or  block  when 
cutting.  The  work  should  be  supported  directly 
underneath  the  point  where  the  cutting  is  to  be 
done;  and  the  solider  the  support,  the  easier  the 
cutting. 

Hammers. — Various  shapes  and  sizes  of  hammers 
are  used,  but  the  commonest,  and  most  convenient 
for  ordinary  use,  is  the  ball  pene-hammer  shown  in 

Fig.  5- 

The  large  end  is  used  for  ordinary  work,  and 
the  small  ball  end,  or  pene,  for  riveting,  scarfing, 


GENERAL   DESCRIPTION   OP   FORGE   AND    TOOLS.  II 


etc.  These  hammers  vary  in  weight  from  a  few 
ounces  up  to  several  pounds.  For  ordinary  use 
about  a  i  J-  or  2-pound  hammer  is  used. 

Several  other  types  in  ordinary  use  are  illustrated 


FIG.  5. 


FIG.  6. 


in  Fig.  6.  A  is  a  straight-pene ;  B,  a  cross-pene; 
and  C,  a  riveting-hammer. 

Sledges. — Very  light  sledges  are  sometimes  made 
the  same  shape  as  ball-pene  hammers.  They  are 
used  for  light  tool- work  and  boiler- work. 

Fig.  7  illustrates  a  common  shape  for  sledges. 
This  is  a  double-faced  sledge. 


FIG.  7. 


FIG.  8. 


Sledges  are  also  made  with  a  cross-pene  or  straight* 
pene,  as  shown  in  Fig.  8. 


12 


FORGE-PRACTICE. 


For  ordinary  work  a  sledge  should  weigh  about 
10  or  12  Ibs. ;  for  heavy  work,  from  16  to  20. 

Sledges  for  light  work  weigh  about  5  or  6  Ibs. 

Tongs. — Tongs  are  made  in  a  wide  variety  of 
shapes  and  sizes,  depending  upon  the  work  they 
are  intended  to  hold.  Three  of  the  more  ordinary 
shapes  are  illustrated. 

The  ordinary  straight- jawed  tongs  are  shown  in 
Fig.  9.  They  are  used  for  holding  flat  iron.  For 
holding  round  iron  the  jaws  are  grooved  or  bent 
to  the  shape  of  the  piece  to  be  held. 

Fig.  10  shows  a  pair  of  bolt-tongs.  These  tongs 
are  used  for  holding  bolts  or  pieces  which  are  larger 
on  the  end  than  through  the  body,  and  are  so 
shaped  that  the  tongs  do  not  touch  the  enlarged  end 
when  the  jaws  grip  the  body  of  the  work. 


FIG.  9. 


FIG.  10. 


FIG.  ii. 


Pick-up  tongs,  Fig.  n,  are  used  for  handling 
small  pieces,  tempering,  etc.,  but  are  very  seldom 
used  for  holding  work  while  forging. 


GENERAL   DESCRIPTION   OF    FORGE    AND   TOOLS.  13 

Fitting  Tongs  to  Work. — Tongs  should  always  be 
carefully  fitted  to  the  work  they  are  intended  to 
hold. 

Tongs  which  fit  the  work  in  the  manner  shown 
in  Fig.  12  should  not  be  used  until  morfe  carefully 
fitted.  In  the  first  case  shown,  the  jaws  are  too 
close  together;  and  in  the  second  case,  too  far 
apart. 


FIG.  12. 


FIG.  13. 

When  properly  fitted,  the  jaws  should  touch 
the  work  the  entire  length,  as  illustrated  in  Fig. 
13.  With  properly  fitted  tongs  the  work  may  be 
held  firmly,  but  if  fitted  as  shown  in  Fig.  12  there 
is  always  a  very  "wobbly"  action  between  the 
jaws  and  the  work. 

To  fit  a  pair  of  tongs  to  a  piece  of  work,  the  jaws 
should  be  heated  red-hot,  the  piece  to  be  held 
placed  between  them,  and  the  jaws  closed  down 
tight  around  the  piece  with  a  hammer.  To  pre- 
vent the  handles  from  being  brought  too  close 
together  while  the  tongs  are  being  fitted,  a  short 
piece  of  stock  should  be  held  between  them  just 


FORGE-PRACTICE. 


back  of  the  jaws.     If  the  handles  are  too  far  apart 

a  few  blows  just  back  of  the  eye  will  close  them  up. 

Flatter — Set-hammer— Swage — Fuller — Swage-block. 

— Among  the  commonest  tools  used  in  forge-work 
are  the  ones  mentioned  above. 

The  flatter,  Fig.  14,  as  its  name  implies,  is  used 
for  flattening  and  smoothing  straight  surfaces. 

The  face  of  the  flatter  is  generally  from  2  inches 
to  3  inches  square,  and  should  be  kept  perfectly 
smooth  with  the  edges  slightly  rounding. 


FIG.  14. 


FIG.  15. 


Fig.  15  shows  a  set-hammer.  This  is  used  for 
finishing  parts  which  cannot  be  reached  with  the 
flatter,  up  into  corners,  and  work  of  that  character. 
The  face  of  this  tool  also  should  be  smooth  and 
flat,  with  the  corners  more  or  less  rounded,  depend- 
ing on  the  work  it  is  intended  to  do. 

Set-hammers  for  small  work  should  be  about 
i  or  ij  inches  square  on  the  face. 

" Set-hammer"  is  a  name  which  is  sometimes 
given  to  almost  any  tool  provided  with  a  handle, 
which  tool  in  use  is  held  in  place  and  struck  with, 
another  hammer.  Thus,  flatters,  swages,  fullers, 
etc.,  are  sometimes  classed  under  the  general  name 
of  set-hammers. 


GENERAL   DESCRIPTION   OF   FORGE   AND    TOOLS.  1 5 

Fullers,  Fig.  16,  are  used  for  finishing  up  filleted 
corners,  forming  grooves,  and  for  numerous  pur- 
poses which  will  be  given  more  in  detail  later. 

They  are  made  in  a  variety  of  sizes,  the  size 
being  determined  by  the  shape  of  the  edge  A. 
On  a  J  inch  fuller  this  edge  would  be  a  half -circle 
J  inch  in  diameter ;  on  a  f  inch  it  would  be  J  inch 
in  diameter,  etc. 

Fullers  are  made  "top"  and  "bottom."  The 
one  shown  with  a  handle  is  a  "top"  fuller,  and 
the  lower  one  in  the  illustration  is  a  "bottom" 
fuller  and  has  the  stem  forged  to  fit  into  the  square 
hardie-hole  of  the  anvil.  This  stem  should  be  a 
loose  fit  in  the  hardie-hole.  Tools  of  this  character 
should  never  be  used  on  an  anvil  where  they  fit 
so  tightly  that  it  is  necessary  to  drive  them  into 
place. 

A  top  and  bottom  swage  is  shown  in  Fig.  17. 
The  swages  shown  here  are  for  finishing  round 


FIG.  16. 


FIG.  18. 


FIG.  17. 

work;    but  swages  are  made  to  be  used  for  other 
shapes  as  well. 


1 6  FORGE-PRACTICE. 

Swages  are  sized  according  to  the  shape  they  are 
made  to  fit.  A  i-inch  round  swage,  for  instance, 
is  made  to  fit  a  circle  i  inch  in  diameter,  and  would 
be  used  for  finishing  work  of  that  size. 

All  of  the  above  tools  are  made  of  low-carbon 
tool  steel. 

A  swage-block  is  shown  in  Fig.  18.  These  blocks 
are  made  in  a  variety  of  shapes;  the  illustration 
showing  a  common  form  for  general  use.  This 
block  is  made  of  cast  iron  and  is  about  3^  inches 
thick.  It  has  a  wide  range  of  uses  and  is  very 
convenient  for  general  work,  where  it  takes  the 
place  of  a  good  many  special  tools. 


CHAPTER  II. 

WELDING. 

Welding-heat. — A  piece  of  wrought  iron  or  mild 
steel,  when  heated,  as  the  temperature  increases 
becomes  softer  and  softer  until  at  last  a  heat  is 
reached  at  which  the  iron  is  so  soft  that  if  another 
piece  of  iron  heated  to  the  same  point  touches  it, 
the  two  will  stick  together.  The  heat  at  which 
the  two  pieces  will  stick  together  is  known  as  the 
welding-heat.  If  the  iron  is  heated  much  beyond 
this  point,  it  will  burn.  All  metals  cannot  be  welded 
(in  the  sense  in  which  the  term  is  ordinarily  used). 
Some,  when  heated,  remain  very  dense  and  retain 
almost  their  initial  hardness  until  a  certain  heat 
is  reached,  when  a  very  slight  rise  of  temperature 
will  cause  them  to  either  crumble  or  melt.  Only 
those  metals  which,  as  the  temperature  is  increased, 
become  gradually  softer,  passing  slowly  from  the 
solid  to  the  liquid  state,  can  be  welded  easily. 
Metals  of  this  kind  just  before  melting  become 
soft  and  more  or  less  pasty,  and  it  is  in  this  con- 
dition that  they  are  most  weldable.  The  greater 
the  range  of  temperature  through  which  the  metal 
remains  pasty  the  more  easily  may  it  be  welded. 

In  nearly  all  welding  the  greatest  trouble  is  in 
heating  the  metal  properly.  The  fire  must  be  clean 

17 


1 8  FORGE-PRACTICE. 

and  bright  or  the  result  will  be  a  " dirty"  heat; 
that  is,  small  pieces  of  cinder  and  other  dirt  will 
stick  to  the  metal,  get  in  between  the  two  pieces, 
and  make  a  bad  weld. 

Too  much  care  cannot  be  used  in  welding ;  if  the 
pieces  are  too  cold  they  will  not  stick,  and  no 
amount  of  hammering  will  weld  them.  On  the 
other  hand,  if  they  are  kept  in  the  fire  too  long 
and  heated  to  too  high  a  temperature  they  will 
be  burned,  and  burned  iron  is  absolutely  worthless. 

The  heating  must  be  done  slowly  enough  to 
insure  the  work  heating  evenly  all  the  way  through. 
If  heated  too  rapidly,  the  outside  may  be  at  the 
proper  heat  while  the  interior  metal  is  much  colder ; 
and,  as  soon  as  taken  from  the  fire,  this  cooler 
metal  on  the  inside  and  the  air  almost  instantly 
cool  the  surface  to  be  welded  below  the  welding 
temperature,  and  it  will  be  too  cold  to  weld  by 
the  time  any  work"  can  be  done  on  it. 

If  the  pieces  are  properly  heated  (when  welding 
wrought  iron  or  mild  steel),  they  will  feel  sticky 
when  brought  in  contact. 

When  welding,  it  is  best  to  be  sure  that  every- 
thing is  ready  before  the  iron  is  taken  from  the 
fire.  All  the  tools  should  be  so  placed  that  they 
may  be  picked  up  without  looking  to  see  where 
they  are.  The  face  of  the  anvil  should  be  perfectly 
clean,  and  the  hammer  in  such  a  position  that  it 
will  not  be  knocked  out  of  the  way  when  the  work 
is  placed  on  the  anvil  for  welding. 

All  the  tools  being  in  place,  and  the  iron  brought 
to  the  proper  heat,  the  tongs  should  be  held  in 


WELDING.  19 

such  a  way  that  the  pieces  can  be  easily  placed  in 
position  for  welding  without  changing  the  grip  or 
letting  go  of  them ;  then,  when  everything  is  ready, 
the  blast  should  be  shut  off,  the  pieces  taken  from 
the  fire,  placed  together  on  the  anvil,  and  welded 
together  with  rapid  blows  of  the  hammer,  welding 
(after  the  pieces  are  once  stuck  together)  the 
thin  parts  first,  as  these  are  the  parts  which 
naturally  cool  the  quickest. 

Burning  Iron  or  Steel. — The  statement  that  iron 
can  be  burned  seems  to  the  beginner  to  be  rather 
exaggerated.  The  truth  of  this  can,  however,  be 
very  easily  shown.  If  a  bar  of  iron  be  heated  in  the 
forge  and  considerable  blast  turned  on,  the  bar  will 
grow  hotter  and  hotter,  until  at  last  sparks  will  be 
seen  coming  from  the  fire.  These  sparks,  which  are 
quite  unlike  the  ordinary  ones  from  the  fire,  are 
white  and  seem  to  explode  and  form  little  white 
stars. 

These  sparks  are  small  particles  of  burning  iron 
which  have  been  blown  upward  out  of  the  fire. 

The  same  sparks  may  be  made  by  dropping  fine 
iron-filings  into  a  gas -flame,  or  by  burning  a  piece 
of  oily  waste  which  has  been  used  for  wiping  up 
iron-filings. 

If  the  bar  of  iron  be  taken  from  the  fire  at  the 
time  these  sparks  appear,  the  end  of  the  bar  will 
seem  white  and  sparkling,  with  sparks,  like  stars 
similar  to  those  in  the  fire,  coming  from  it.  If  the 
heating  be  continued  long  enough,  the  end  of  the 
bar  will  be  partly  consumed,  forming  lumps  similar 
to  the  "clinkers"  taken  from  a  coal  fire. 


20  FORGE-PRACTICE. 

To  burn  iron  two  things  are  necessary :  a  high 
enough  heat,  and  the  presence  of  oxygen. 

As  noted  before,  when  welding,  care  must  be 
taken  not  to  have  too  much  air  going  through  the 
fire;  in  other  words,  not  to  have  an  oxidizing  fire. 

If  the  fire  is  not  an  oxidizing  one,  there  is  not  so 
much  danger  of  injury  to  the  iron  by  burning  and 
the  forming  of  scale. 

Iron  which  has  been  overheated  and  partially 
burned  has  a  rough,  spongy  appearance  and  is 
brittle  and  crumbly. 

Use  of  Fluxes  in  Welding. — When  a  piece  of  iron 
or  steel  is  heated  for  welding  under  ordinary  con- 
ditions the  outside  is  oxidized;  that  is,  a  thin  film 
of  iron  oxide  is  formed.  This  oxide  is  the  black 
scale  which  is  continually  falling  from  heated  iron 
and  is  formed  when  heated  iron  is  brought  in  contact 
with  the  air.  This  oxide  of  iron  is  not  fluid  except 
at  a  very  high  heat,  and,  if  allowed  to  stay  on  the 
iron,  will  prevent  a  good  weld. 

When  welding  without  a  flux  the  iron  is  brought 
to  a  high  enough  heat  to  melt  the  oxide,  which  is 
forced  from  between  the  welding  pieces  by  the 
blows  of  the  hammer. 

This  heat  may  easily  be  taken  when  welding 
ordinary  iron;  but  when  working  with  some  ma- 
chine-steel, and  particularly  tool-steel,  the  metal 
cannot  be  heated  to  a  high  enough  temperature 
to  melt  the  oxide  without  burning  the  steel. 

From  the  above  it  would  seem  impossible  to  weld 
steel,  as  it  cannot  be  heated  under  ordinary  condi- 
tions without  oxidizing,  but  by  the  use  of  a  flux 


WELDING.  2 1 

this    difficulty    may    be   overcome    and   the   oxide 
melted  at  a  lower  temperature. 

The  flux  (sand  and  borax  are  the  most  common) 
should  be  sprinkled  on  the  part  of  the  piece  to  be 
welded  when  it  has  reached  about  a  yellow  heat, 
and  the  heating  continued  until  the  metal  is  at  a 
proper  temperature  to  be  soft  enough  to  weld,  but 
care  should  be  taken  to  see  that  the  flux  covers 
the  parts  to  be  welded  together. 

The  flux  has  a  double  action;  in  the  first  place, 
as  it  melts  it  flows  over  the  piece  and  forms  a 
protecting  covering  which  prevents  oxidation, 
and  also  when  raised  to  the  proper  heat  dissolves 
the  oxide  that  has  already  formed. 

The  oxide  melts  at  a  much  lower  heat  when 
combined  with  the  flux  than  without  it,  and  to 
melt  the  oxide  is  the  principal  use  of  the  flux.  The 
metal  when  heated  in  contact  with  the  flux  becomes 
soft  and  "weldable"  at  a  lower  temperature  than 
when  without  it. 

Ordinary  borax  contains  water  which  causes  it 
to  bubble  up  when  heated.  If  the  heating  is  con- 
tinued at  a  high  temperature,  the  borax  melts 
and  runs  like  water;  this  melted  borax,  when 
cooled,  is  called  borax-glass. 

Borax  for  welding  is  sometimes  fused  as  above 
and  then  powdered  for  use. 

Sal  ammoniac  mixed  with  borax  seems  to  clean 
the  surface  better  than  borax  alone.  A  flux  made 
of  one  part  of  sal  ammoniac  and  four  parts  borax 
works  well,  particularly  when  welding  tool-steel, 
and  is  a  little  better  than  borax  alone. 


22  FORGE-PRACTICE. 

Most  patented  welding  compounds  have  borax 
as  a  basis,  and  are  very  little,  if  any,  better 
than  the  ordinary  mixture  given  above. 

The  flux  does  not  in  any  way  stick  the  pieces 
together  or  act  as  a  cement  or  glue.  Its  use  is 
principally  to  help  melt  the  oxide  already  formed 
and  to  prevent  the  formation  of  more. 

Iron  filings  are  sometimes  mixed  with  borax  and 
used  as  a  flux. 

When  using  a  flux  the  work  should  always  be 
scarfed  the  same  as  when  no  flux  is  used.  The 
pieces  can  be  welded,  however,  at  a  lower 
heat. 

Fagot  or  Pile  Welding. — When  a  large  forging 
is  to  be  made  of  wrought  iron,  small  pieces  of 
"scrap"  iron  (old  horseshoes,  bolts,  nuts,  etc.) 
are  placed  together  in  a  square  or  rectangular 
pile  on  a  board,  bound  together  with  wire,  heated 
to  welding  heat  in  a  furnace,  and  welded  together 
into  one  solid  lump,  and  the  forging  made  from 
this.  If  there  is  not  enough  metal  in  one  lump, 
several  are  made  in  this  way  and  afterward  welded 
to  each  other — making  one  large  piece.  This  is 
known  as  fagot  or  pile  welding. 

Sand  is  used  for   fluxing  to  a 
large  extent  on  work  of  this  kind. 
Sometimes  a  small  fagot  weld 
is  made  by  laying  two  or  more 
pieces  together  and  welding  them 
their  entire  length,  or  one  piece 
may  be  doubled  together  several 
times  and  welded  into   a   lump.      Such  a  weld  is 


WELDING.  23 

shown  in   Fig.    19,    which  shows   the  piece  before 
welding  and  also  after  being  welded  and  shaped. 

Scarfing. — In  a  fagot  weld  the  pieces  are  not 
prepared  or  shaped  for  each  other,  being  simply  laid 
together  and  welded,  but  for  most  welding  the 
ends  of  the  pieces  to  be  joined  should  be  so  shaped 
that  they  will  fit  together  and  form  a  smooth 
joint  when  welded.  This  is  called  scarfing.  It 
is  very  important  that  the  scarfing  be  properly 
done,  as  a  badly  shaped  scarf  will  probably  spoil 
the  weld.  For  instance,  if  an  attempt  be  made 
to  weld  two  bars  together  simply  by  overlapping 
their  ends,  as  in  Fig.  20,  the  weld  when  finished 
would  be  something  like  Fig.  21.  Each  bar  would 


FIG.  20. 


FIG.  21. 

be  forged  into  the  other  and  leave  a  small  crack 
where  the  end  came.  On  the  other  hand,  if  the 
ends  of  the  bars  were  properly  scarfed  or  pointed, 
they  could  be  welded  together  and  leave  no  mark — 
making  a  smooth  joint. 

Lap-welds  are  sometimes  made  without  scarf- 
ing when  manufacturing  many  pieces  alike,  but 
this  should  not  be  attempted  in  ordinary  work. 


24  FORGE-PRACTICE. 

Lap-weld  Scarf. — In  preparing  for  the  lap-weld, 
the  ends  of  the  pieces  to  be  welded  should  be  first 
upset  until  they  are  considerably  thicker  than  the 
rest  of  the  bar.  This  is  done  to  allow  for  the 
iron  which  burns  off,  or  is  lost  by  scaling,  and 
also  to  allow  for  the  hammering  which  must  .be 
done  when  welding  the  pieces  together.  To  make 
a  proper  weld  the  joint  should  be  well  hammered 
together,  and  as  this  reduces  the  size  of  the  iron 
at  that  point  the  pieces  must  be  upset  to  allow 
for  this  reduction  in  size  in  order  to  have  the  weld 
the  same  size  as  the  bar. 

If  the  ends  are  not  upset  enough  in  the  first 
place,  it  requires  considerable  hard  work  to  upset 
the  weld  after  they  are  joined  together.  Too 
much  upsetting  does  no  harm,  and  the  extra 
metal  is  very  easily  worked  into  shape.  To  be  on 
the  safe  side  it  is  better  to  upset  a  little  more  than 
is  absolutely  necessary — it  may  save  considerable 
work  afterwards. 

If  more  than  one  heating  will  be  necessary  to 
make  a  weld,  the  iron  should  be  upset  just  that 
much  more  to  allow  for  the  extra  waste  due  to 
the  second  or  third  heating. 

Flat  Lap-weld. — The  lap-weld  is  the  weld  ordinarily 
used  to  join  flat  or  round  bars  of  iron  together 
end  to  end. 

Following  is  a  description  of  a  flat  lap-weld: 
The  ends  of  the  pieces  to  be  joined  must  be  first 
upset.  When  heating  for  upsetting  heat  only  the 
end  as  shown  in  Fig.  22,  where  the  shaded  part 
indicates  the  hotter  metal.  To  heat  this  way 


WELDING. 


place  only  the  extreme  end  of  the  bar  in  the  fire, 
so  the  heat  will  not  run  back  too  far.  The  end 
should  be  upset  until  it  looks  about  like  Fig.  23. 


FIG.  22. 


FIG.  23. 


When  starting  to  shape  the  scarf  use  the  round 
or  pene  end  of  the  hammer.  Do  not  strike  directly 
down  on  the  work,  but  let  the  blows  come  at  an 
angle  of  about  45  degrees  and  in  such  a  way  as  to 
force  the  metal  back  toward  the  base  as  shown  in  Fig. 


FIG.  24. 


FIG.  25. 


24.  This  drives  the  metal  back  and  makes  a  sort  of 
thick  ridge  at  the  beginning  of  the  scarf.  In 
finishing  the  scarf,  use  the  flat  face  of  the  hammer, 
and  bring  the  piece  to  the  very  edge  of  the  anvil, 
as  in  this  way  a  hard  blow  may  be  struck  without 
danger  of  hitting  the  anvil  instead  of  the  work. 
The  proper  position  is  shown  in  Fig.  25. 

The  scarfs  should  be  shaped  as  in  Fig.  26,  leav- 
ing them  slightly  convex  and  not  concave,  as 
shown  in  Fig.  27. 


26  FORGE-PRACTICE. 

The  reason  for  this  is  that  if  the  scarfed  ends  be 
concave  when  the  two  pieces   are  put  together,  a 


FIG.  26.  FIG.  27. 

small  pocket  or  hollow  will  be  left  between  them, 
the  scarfs  touching  only  the  edges.  When  the 
weld  is  hammered  together,  these  edges  being  in 
contact  will  naturally  weld  first,  closing  up  all 
outlet  to  the  pocket.  As  the  surface  of  the  scarf 
is  more  or  less  covered  with  melted  scale  and 
other  impurities,  some  of  this  will  be  held  in  the 
pocket  and  make  a  bad  place  in  the  weld.  On 
the  other  hand,  if  the  scarfs  are  convex,  the  metal 
will  first  stick  in  the  very  center  of  the  scarf,  forc- 
ing out  the  melted  scale  at  the  sides  of  the  joint 
as  the  hammering  continues. 

The  length  of  the  scarf  should  be  about  i£  times 
the  thickness  of  the  bar;  thus  on  a  bar  J"  thick 
the  scarf  should  be  about  J"  long. 

The  width  of  the  end  A  should  be  slightly  less 
than  the  width  B  of  the  bar.  In  welding  the  two 
pieces  together,  the  first  piece  should  be  placed 
scarf  side  up  on  the  anvil,  and  the  second  piece 
laid  on  top,  scarf  side  down,  in  such  a  way  that 
the  thin  edges  of  the  second  piece  will  lap  over 
the  thick  ridge  C  on  the  first  piece  as  shown  in 
Fig.  28.  The.  piece  which  is  laid  on  top  should 
be  held  by  the  smith  doing  the  welding,  the  other 
may  be  handled  by  the  helper. 


WELDING.  27 

The  helper  should  place  his  piece  in  position 
on  the  anvil  first.  As  it  is  rather  hard  to  lay  the 
other  piece  directly  on  top  of  this  and  place  it 
exactly  in  the  right  position,  it  is  better  to  rest 
the  second  piece  on  the  corner  of  the  anvil  as 


FIG.  28.  FIG.  29. 

shown  at  A,  Fig.  29,  and  thus  guide  it  into  position. 
In  this  way  the  piece  may  be  steadied  and  placed 
on  the  other  in  the  right  position  without  any 
loss  of  time. 

When  heating  for  a  lap-weld,  or  for  that  matter 
any  weld  where  two  pieces  are  joined  together, 
great  care  should  be  taken  to  bring  both  pieces 
to  the  same  heat  at  the  same  time.  If  one  piece 
heats  faster  than  the  other,  it  should  be  taken 
from  the  fire  and  allowed  to  cool  until  the  other 
piece  " catches  up"  with  it.  It  requires  some 
practice  to  so  place  the  pieces  in  the  fire  that  they 
will  be  heated  uniformly  and  equally.  The  tips 
particularly  must  be  watched,  and  it  may  be 
necessary  to  cool  them  from  time  to  time  in  the 
water-bucket  to  prevent  the  extreme  ends  from 
burning  off. 

The  fire  must  be  clean,  and  the  heating  should  be 
done  slowly  in  order  to  insure  its  being  done  evenly. 

Just  before  taking  the  pieces  from  the  firs  they 


28  FORGE-PRACTICE. 

should  be  turned  scarf  side  down  for  a  short  tima 
to  be  sure  that  the  surfaces  to  be  joined  will  be  hot. 
More  blast  should  be  used  at  the  last  moment 
than  when  starting  to  heat. 

The  only  way  to  know  how  this  heating  is  going 
on  is  to  take  the  pieces  from  the  fire  from  time 
to  time  and  look  at  them.  The  color  grows  lighter 
as  the  temperature  increases,  until  finally,  when 
the  welding  heat  is  reached,  the  iron  will  seem 
almost  white.  The  exact  heat  can  only  be  learned 
by  experience;  but  the  workman  should  recognize 
it  after  a  little  practice  as  soon  as  he  sees  it. 

To  get  an  indication  of  the  heat,  which  will  help 
sometimes,  watch  the  sparks  that  come  from  the 
fire.  When  the  little,  white,  explosive  sparks 
come  they  show  that  some  of  the  iron  has  been 
heated  hot  enough  to  be  melted  off  in  small  particles 
and  is  burning.  This  serves  as  a  rough  indication 
that  the  iron  is  somewhere  near  the  welding  heat. 
This  should  never  be  relied  on  entirely,  as  the 
condition  of  the  fire  has  much  to  do  with  their 
appearance. 

Round  Lap-weld. — The  round  lap-weld — the  weld 
used  to  join  round  bars  end  to  end — is  made  in 
much  the  same  way  as  the  ordinary  or  flat  lap- 
weld.  The  directions  given  for  making  the  flat 
weld  apply  to  the  round  lap  as 
well,  excepting  that  the  scarf 
is  slightly  different  in  shape. 
The  proper  shape  of  scarf  is 
shown  in  Fig.  30,  which  gives 
the  top  and  side  views  of  the  piece.  One  side  is 


WELDING.  29 

left  straight,  the  other  three  sides  tapering  in 
to  meet  it  in  a  point.  The  length  of  the  scarf 
should  be  about  one  and  one-half  times  the 
diameter  of  the  bar.  Always  be  sure,  particularly 
in  small  work,  that  the  pieces  are  scarfed  to  a 
point,  and  not  merely  flattened  out.  The  greatest 
difficulty  with  this  weld  is  to  have  the  points  of 
the  pieces  well  welded,  as  they  cool  very  rapidly 
after  leaving  the  fire.  The  first  blows,  after  stick- 
ing the  pieces  together,  should  cover  the  points. 
The  weld  should  be  made  square  at  first  and  then 
rounded.  The  weld  is  not  so  apt  to  split  while 
being  hammered  if  welded  square  and  then  worked 
round,  as  it  would  be  if  hammered  round  at  first. 

If  the  scarf  were  made  wide  on  the  end  like 
the  ordinary  lap-weld,  it  would  be  necessary  to 
hammer  clear  around  the  bar  in  order  to  close 
down  the  weld;  but  with  the  pointed  scarf,  one 
blow  on  each  point  will  stick  the  work  in  place, 
making  it  much  more  quickly  handled. 

Ring  Weld,  Round  Stock.  A  ring  formed  from 
round  stock  may  be  made  in  two  ways;  that  is, 
by  scarfing  before  or  after  bending  into  shape. 
When  scarfed  before  bending,  the  length  of  stock 
should  be  carefully  calculated,  a  small  amount 


FIG.  31. 

being    added  for  welding,  and  the  ends  upset  and 
scarfed  exactly  the  same  as  for  a  round  lap-weld. 


30  FORGE  PRACTICE. 

Care  should  be  taken  to  see  that  the  scarfs  come 
on  opposite  sides  of  the  piece. 

Fig.  31  shows  a  piece  of  stock  scarfed  ready  for 
bending. 

After   scarfing,  the    piece    should    be  bent    into 

a  ring  and  welded,  care 
being  taken  when  bend- 
ing to  see  that  the  points 
of  the  scarf  lie  as  indi- 
cated at  A,  Fig.  32,  and 
not  as  shown  at  B. 

When  the  points  of 
the  scarfs  are  lapped  as 
shown  at  A,  most  of  the 
welding  may  be  done 
while  the  ring  lies  flat  on 
the  anvil,  the  shaping 
being  finished  over  the 
FIG.  32.  horn.  If  the  points  are 

lapped  the  other  way,  B,  the  welding  also  must 
be  done  over  the  horn,  making  it  much  more  awk- 
ward to  handle. 

The  second  way  of  welding  the  ring  is  practically 
the  same  as  that  of  making  a  chain  link,  and  the 
same  description  of  scarfing  will  answer  for  both, 
the  stock  being  cut  and  bent  into  a  ring,  with  the 
ends  a  little  distance  apart;  these  ends  are  then 
scarfed  the  same  as  described  below  for  a  link 
scarf  and  welded  in  exactly  the  same  manner 
as  described  for  making  the  other  ring. 

Chain-making. — The  first  step  in  making  a  link 
is  to  bend  the  iron  into  a  U-shaped  piece,  being 


WELDING.  31 

careful  to  keep  the  legs  of  the  U  exactly  even  in 
length.  The  piece  should  be  gripped  at  the  lower 
end  of  the  U,  the  two  ends  brought  to  a  high  heat, 
scarfed,  bent  into  shape  together,  reheated,  and 
welded. 

To  scarf  the  piece  place  one  end  of  the  U  on  the 
anvil,  as  shown  in  Fig.  33,  and  strike  one  blow  on 
it ;  move  it  a  short  distance  in  the  direction  shown 
by  the  arrow  and  strike  another  blow.  This 
should  be  continued  until  the  edge  or  corner  of 
the  piece  is  reached,  moving  it  after  each  blow. 


FIG.  33.  FIG.  34. 

This  operation  leaves  a  series  of  little  steps  on 
the  end  of  the  piece,  and  works  it  out  in  a  more 
or  less  pointed  shape,  as  shown  in  Fig.  34. 

This  scarf  may  be  finished  by  being  brought 
more  to  a  point  by  a  few  blows  over  the  horn  of 
the  anvil.  The  ends  should  then  be  bent  together 
and  welded.  Fig.  35  shows  the  steps  in  making 
the  link  and  two  views  of  the  finished  link.  The 
link  is  sometimes  left  slightly  thicker  through 
the  weld.  A  second  link  is  made — all  but  welding — 
spread  open,  and  the  first  link  put  on  it,  closed 
up  again,  and  welded.  A  third  is  joined  to  this 
etc. 

When  made  on  a  commercial  scale,  the  links  are 


FORGE-PRACTICE. 


not  scarfed  but  bent  together  and  welded  in  one 
heat. 


\ 


A 

1 
B 

V                / 

<x 

FIG.  35. 
Ring,  or  Band. — A  method  of  making  a  ring  from 


FIG.  36. 

flat  iron  is   shown  in   Fig.    36,   which  shows  the 
stock  before  and  after  bending  into  shape. 


WELDING.  33 

The  stock  is  cut  to  the  correct  length,  upset, 
and  scarfed  exactly  the  same  as  for  a  flat  lap-weld. 
The  piece  is  bent  into  shape  and  welded  over  the 
horn  of  the  anvil.  The  ring  must  be  heated  for 
welding  very  carefully  or  the  outside  lap  will 
burn  before  the  inside  is  hot  enough  to  weld. 

In  scarfing  this — as  in  making  other  rings — care 
must  be  taken  to  have  the  scarfs  come  on  opposite 
sides  of  the  tock. 

Washer,  or  Flat  Ring.  —  In  this  weld  flat  stock 
is  used  bent  edgewise  into  a  ring  without  any 
preparation.  The  corners  of  the  ends  are  trimmed 
off  parallel  after  the  stock  is  bent  as  shown  in 
Fig.  37- 


FIG.  37.  FIG.  38. 

After  trimming  the  ends  are  scarfed  with  a 
fuller  or  pene  end  of  a  hammer  and  lapped  ready 
for  welding  (Fig.  38). 

When  heating  for  welding,  the  ring  should  be 
turned  over  several  times  to  insure  uniformity  in 
heating. 

If  the  work  is  particular,  the  ends  of  the  stock 
should  be  upset  somewhat  before  bending  into 
shape. 


34  FORGE-PRACTICE. 

Butt-weld.  —  This  is  a  weld  where  the  pieces 
are  butted  together  without  any  slanting  scarfs, 
leaving  a  square  joint  through  the  weld. 

When  two  pieces  are  so  welded  the  ends  should 
be  slightly  rounded,  simillar  to  Fig.  39,  which 
shows  two  pieces  ready  for  welding.  If  the  ends 
are  convex  as  shown,  the  scale  and  other  impurity 
sticking  to  the  metal  is  forced  out  of  the  joint. 
If  the  ends  were  concave  this  matter  would  be 


r 


FIG.  39.  FIG.  40. 

held  between  the  pieces  and  make  a  poor  weld. 
The  pieces  are  welded  by  being  struck  on  the  ends 
and  driven  together.  This,  of  course,  upsets  the 
metal  near  the  weld  and  leaves  the  piece  something 
like  Fig.  40,  showing  a  slight  seam  where  the 
rounded  edges  of  the  ends  join.  This  upset  part 
is  worked  down  to  size  at  a  welding  heat,  leaving 
the  bar  smooth. 

A  butt-weld  is  not  as  safe  or  as  strong  as  a  lap- 
weld. 

When  the  pieces  are  long  enough  they  may  be 
welded  right  in  the  fire.  This  is  done  by  placing 
the  pieces  in  the  fire  in  the  proper  position  for 
welding;  a  heavy  weight  is  held  against  the  pro- 
jecting end  of  one  piece — to  "back  it  up" — and 
the  weld  is  made  by  driving  the  pieces  together 
by  hammering  on  the  projecting  end  of  the  second 
piece.  As  soon  as  the  work  is  "stuck,"  the  weld 


WELDING.  35 

is  taken  from  the  fire  and  finished  on  the 
anvil. 

Jump  Weld. — Another  form  of  butt-weld,  Fig.  41, 
is  the  "jump"  weld,  which, 
however,  is  a  form  which  should 
be  avoided  as  much  as  possible, 
as  it  is  very  liable  to  be  weak. 
When  making  a  weld  like  this,  the 
piece  which  is  to  be .  "  jumped," 
or  "butted,"  on  to  the  other  FIG.  41. 

piece  should  have  its  end  upset  in  such  a  way  as 
to  flare  out  and  form  a  sort  of  flange  the  wider 
the  better.  When  the  weld  is  made,  this  flange — 
indicated  by  the  arrow — can  be  welded  down  with  a 
hammer,  or  set-hammers,  and  make  a  fairly  strong 
weld. 

Split  Weld;  Weld  for  very  Thin  Steel. — Very  thin 
stock  is  sometimes  difficult  to  join  with  the  ordi- 
nary lap -weld  for  the  reason  that  the  stock  is  so 
thin  that  if  the  pieces  are  taken  from  the  fire  at  the 
proper  heat  they  will  be  too  cold  to  weld  before 
they  can  be  properly  placed  together  on  the  anvil. 

This  difficulty  is  somewhat  overcome  by  scarfing 
the  ends,  similar  to  Fig.  42.  The  ends  are  tapered 


FIG.  42. 

to  a  blunt  edge  and  split  down  the  center  for  half  an 
inch  or  so,  depending  on  the  thickness  of  stock. 
One  half  of  each  split  end  is  bent  up,  the  other 


FORGE-PRACTICE. 


down;    the  ends  are  pushed  tightly  together   and 
the  split  parts  closed  down  on  each  other,  as  shown 


FIG.  43. 

in  Fig.  43.  The  joint  may  then  be  heated  and 
welded. 

This  is  a  weld  sometimes  used  for  welding  spring 
steel,  or  iron  to  steel. 

Split  Weld;  Heavier  Stock. — A  split  weld  for 
heavier  stock  is  shown  ready  for  welding  in  Fig. 


FIG.  44 


FIG.  45- 


FIG.  46. 

45,  Fig.  44  showing  the  two  pieces  before  they  are 
put  together.  In  this  weld  the  ends  of  the  pieces 
are  first  upset  and  then  scarfed,  one  piece  being 


WELDING.  37 

split  and  shaped  into  a  Y,  while  the  other  has  its 
end  brought  to  a  point  with  the  sides  of  the  bar 
just  back  of  the  point  bulging  out  slightly  as  shown 
at  A  and  B.  This  bulge  is  to  prevent  the  two 
pieces  from  slipping  apart. 

When  properly  shaped  the  two  pieces  are  driven 
together  and  the  sides,  or  lips,  of  the  Y-shaped 
scarf  closed  down  over  the  pointed  end  of  the  other 
piece.  The  lips  of  the  Y  should  be  long  enough  to 
lap  over  the  bulge  on  the  end  of  the  other  piece 
and  thus  prevent  the  two  pieces  from  slipping  apart. 
The  pieces  are  then  heated  and  welded.  Care  must 
be  taken  to  heat  slowly,  that  the  pointed  part  may 
be  brought  to  a  welding  heat  without  burning  the 
outside  piece.  Borax,  sand,  or  some  other  flux 
should  be  used.  (Sometimes  the  faces  of  the  scarfs 
are  roughened  or  notched  with  a  chisel,  as  shown  in 
Fig.  46,  to  prevent  the  pieces  from  slipping  apart.) 

This  is  the  weld  that  is  often  used  when  welding 
tool-steel  to  iron  or  mild  steel. 

Sometimes  the  pieces  are  heated  separately  to  a 
welding  heat  before  being  placed  together.  Good 
results  may  be  obtained  this  way  when  tool-steel  is 
welded  to  iron  or  mild  steel,  as  the  tool-steel  welds 
at  a  much  lower  temperature  than  either  wrought 
iron  or  mild  steel,  and  if  the  two  pieces  are  heated 
separately,  the  other  metal  may  be  raised  to  a  much 
higher  temperature  than  the  tool-steel. 

Angle  Weld. — In  all  welding  it  should  be  remem- 
bered that  the  object  of  scarfing  is  to  so  shape  the 
pieces  to  be  welded,  that  they  will  fit  together  and 
form  a  smooth  joint  when  properly  hammered. 


FORGE-PRACTICE. 


Frequently  there  are  several  equally  good  methods 
of  scarfing  for  the  same  sort  of  weld,  and  it  should 
be  remembered  that  the  method  given  here  is  not 
necessarily  the  only  way  in  which  the  particular 
weld  can  be  made. 

Fig.  47  shows  one  way  of 
scarfing  for  a  right-angle  weld 
made  of  flat  iron.  Both  pieces 
are  scarfed  exactly  alike.  The 
scarfing  is  done  with  the  pene 
end  of  the  hammer.  If  neces- 
sary the  ends  of  the  pieces 
may  be  upset  before  scarfing. 

As  in  all  other  welds,  care 
must  be  taken  to  so  shape  the 
scarfs  that  when  they  are  placed 
together  they  will  touch  in  the 
center,  and  not  around  the  edges,  thus  leaving  an 
opening  for  forcing  out  the  impurities  which  collect 
on  the  surfaces  to  be  welded. 


FIG.  47- 


FIG.  48. 

"T"  Weld.  —  A  method  of  scarfing   for  a 
weld  is  illustrated  in  Fig.  48. 


WELDING.  39 

The  stem,  A,  should  be  placed  on  the  bar,  B, 
when  welding  in  about  the  position  shown  by  the 
dotted  line  on  B. 

"T"  Weld,  Round  Stock.  —  Two  methods  of 
scarfing  for  a  ' '  T  "  weld  made  from  round  stock  are 
shown  in  Fig.  49. 


FIG.  49. 

The  scarfs  are  formed  mostly  with  the  pene  end 
of  the  hammer. 

The  illustration  will  explain  itself.  The  stock 
should  be  well  upset  in  either  method. 

Welding  Tool  -  steel.  —  The  general  method  of 
scarfing  is  the  same  in  all  welding ;  but  when  tool- 
steel  is  to  be  welded,  either  to  itself  or  to  wrought 
iron  or  mild  steel,  more  care  must  be  used  in  the 
heating  than  when  working  with  the  softer  metals 
alone. 

The  proper  heat  for  welding  tool-steel — about  a 
bright  yellow — can  only  be  learned  by  experiment. 
If  the  tool-steel  is  heated  until  the  sparks  fly,  a 
light  blow  of  the  hammer  will  cause  it  te  crumble 
and  fall  to  pieces. 


40  FORGE-PRACTICE. 

When  welding  mild  steel  or  wrought  iron  to  tool- 
steel,  the  tool-steel  should  be  at  a  lower  heat  than 
the  other  metal,  which  should  be  heated  to  its  reg- 
ular welding  heat. 

The  flux  used  should  be  a  mixture  of  about  one 
part  sal  ammoniac  and  four  parts  borax. 

Tool-steel  of  high  carbon,  and  such  as  is  used  for 
files,  small  lathe  tools,  etc.,  can  seldom  be  welded  to 
itself  in  a  satisfactory  manner.  What  appears  to 
be  a  first-class  weld  may  be  made,  and  the  steel 
may  work  up  into  shape  and  seem  perfect — may,  in 
fact,  be  machined  and  finished  without  showing 
any  signs  of  the  weld — but  when  the  work  is  hard- 
ened, the  weld  is  almost  certain  to  crack  open. 

Spring  steel,  a  lower  carbon  steel,  may  be  satis- 
factorily welded  if  great  care  be  used. 


CHAPTER  III. 

CALCULATION  OF   STOCK   FOR  BENT  SHAPES. 

Calculating  for   Angles  and    Simple    Bends.  —  It    is 

often  necessary  to  cut  the  stock  for  a  forging  as 
nearly  as  possible  to  the  exact  length  needed.  This 
length  can  generally  be  easily  obtained  by  meas- 
ment  or  calculation. 

About  the  simplest  case  for  calculation  is  a  plain 
right-angle  bend,  of  which  the  piece  in  Fig.  50  will 
serve  as  an  example. 

This  piece  as  shown  is  a  simple  right-angle  bend 
made  from  stock  i"  through,  8"  long  on  the  outside 
of  each  leg. 


i 

\ 

i 

" 

E 

s 

i 

1 

r  V" 

— 

-r- 

i- 

R"                     *T 

r 

O                           -*\    l 

FIG.  50. 

FIG.  51. 


Suppose  this  to  be  made  of  wood  in  place  of  iron. 
It  is  easily  seen  that  a  piece  of  stock  i"  thick  and 
15"  long  would  make  the  angle  by  cutting  off  7" 

41 


42  FORGE-PRACTICE. 

from  one  end  and  fastening  this  piece  to  the  end  of 
the  8"  piece,  as  shown  in  Fig.  51. 

This  is  practically  what  is  done  when  the  angle  is 
made  of  iron — only,  in  place  of  cutting  and  fasten- 
ing, the  bar  is  bent  and  hammered  into  shape. 

In  other  words,  any  method  which  will  give  the 
length  of  stock  required  to  make  a  shape  of  uniform 
section  in  wood,  if  no  allowance  is  made  for  cutting 
or  waste,  will  also  give  the  length  required  to  make 
the  same  shape  with  iron. 

An  easier  way — which  will  serve  for  calculating 
lengths  of  all  bent  shapes — is  to  measure  the  length 
of  an  imaginary  line  drawn  through  the  center  of 
the  stock.  Thus,  if  a  dotted  line  should  be  drawn 
through  the  center  of  stock  in  Fig.  50,  the  length  of 
each  leg  of  this  line  would  be  7^" ,  and  the  length  of 
stock  required  15",  as  found  before. 

No  matter  what  the  shape  when  the  stock  is  left 
of  uniform  width  through  its  length,  this  length  of 
straight  stock  may  always  be  found  by  measuring 
the  length  of  the  center  line  on  the  bent  shape. 
This  may  be  clearly  shown  by  the  following  experi- 
ment. 

Experiment  to  Determine  Part  of  Stock  which 
Remains  Constant  in  Length  while  Bending.  —  Sup- 
pose a  straight  bar  of  iron  with  square  ends  be 
taken  and  bent  into  the  shape  shown  in  Fig.  52.  If 

the  length  of  the  bar  be 
measured  on  the  inside 
edge  of  the  bend  and  then 
.  FlG-  52-  on  the  outside,  it  will  be 

found  that  the  inside  length  is  considerably  shorter 


CALCULATION   OF    STOCK    FOR   BENT    SHAPES  43 

than  the  outside ;  and  not  only  this,  but  the  inside 
will  be  shorter  than  the  original  bar,  while  the  out- 
side will  be  longer.  The  metal  must  therefore 
squeeze  together  or  upset  on  the  inside  and 
stretch  or  draw  out  on  the  outside.  If  this  is  the 
case,  as  it  is,  there  must  be  some  part  of  the  bar 
which  when  it  is  bent  neither  squeezes  together  nor 
draws  out,  but  retains  its  original  length,  and  this 
part  of  the  bar  lies  almost  exactly  in  the  center,  as 
shown  by  the  dotted  line.  It  is  on  this  line  of  the 
bent  bar  that  the  measuring  must  be  done  in  order 
to  determine  the  original  length  of  the  straight 
stock,  for  this  is  the  only  part  of  the  stock  which 
remains  unaltered  in  length  when  the  bar  is  bent. 

To  make  the  explanation  a  little  clearer,  suppose 
a  bar  of  iron  is  taken,  polished  on  one  side,  and  lines 
scratched  upon  the  surface,  as  shown  in  the  lower 
drawing  of  Fig.  53,  and  this  bar  then  bent  into  the 
shape  shown  in  the  upper  drawing.  Now  if  the 
length  of  each  one  of  these  lines  be  measured  and 
the  measurements  compared  with  the  length  of  the 
same  lines  before  the  bar  was  bent,  it  would  be 
found  that  the  line  A  A,  on  the  outside  of  the  bar, 
had  lengthened  considerably;  the  line  BB  would 
be  somewhat  lengthened,  but  not  as  much  as  A  A ; 
and  CC  would  be  lengthened  less  than  BB.  The 
line  OO,  through  the  center  of  the  bar,  would  meas- 
ure almost  exactly  the  same  as  when  the  bar  was 
straight.  The  line  DD  would  be  found  to  be 
shorter  than  00  and  FF  shorter  than  any  other. 
The  line  00,  at  the  center  of  the  bar,  does  not 
change  its  length  when  the  bar  is  bent;  conse- 


44 


FORGE-PRACTICE. 


quently,  to  determine  the  length  of   straight  stock 
required    to    bend    into    any    shape,    measure    the 


FIG.  53. 


FIG.  54. 


length  of  the  line  following  the  center  of  the  stock 
of  the  bent  shape. 

As  another  example  Fig.  54  will  serve. 

Suppose  a  center  line  be  drawn,  as  shown  by  the 
dotted  line.  As  the  stock  is  i"  thick,  the  length  of 
the  center  line  of  the  part  A  will  be  5",  at  B  8", 
C  5",  D  2",  E  3i",  and  the  total  length  of  stock 
required  2iJ". 

A  convenient  form  for  making  calculations  is  as 
follows : 

A  =  5" 


Total .    .  .  2 1  \"  =  length  of  stock  required. 

Curves.  Circles.  Methods  of  Measuring.  —  On  cir- 
cles and  curves  there  are  several  different  methods 
which  may  be  employed  in  determining  the  length 
of  stock,  but  the  same  principle  must  be  followed 


CALCULATION    OF    STOCK    FOR   BENT    SHAPES. 


45 


in  any  case  —  the  length  must  be  measured  along 
the  center  line  of  the  stock. 

One  way  of  measuring  is  to  lay  off  the  work  full  size. 
On  this  full-size  drawing  lay  a  string  or  thin,  easily 
bent  wire  in  such  a  way  that  it  follows  the  shape 
of  the  bend  through  its  entire  length,  being  careful 
that  the  string  is  laid  along  the  center  of  the  stock. 

The  string  or  wire  may  then  be  straightened  and 
the  length  measured  directly. 

Irregular  shapes  or  scrolls  are  easily  measured  in 
this  way. 

Another  method  of  measuring  stock  for  scrolls, 
etc.,  is  to  step  around  a  scroll  with  a  pair  of  dividers 
with  the  points  a  short  distance  apart,  and  then  lay 
off  the  same  number  of  spaces  in  a  straight  line  and 
measure  the  length  of  that  line.  This  is  of  more 
use  in  the  drawing-room  than  in  the  shop. 

Measuring-wheel.  —  Still  another  way  of  measuring 
directly  from  the  drawing  is  to  use  a 
light  measuring-  wheel,  similar  to 
the  one  shown  in  Fig.  55,  mounted 
in  some  sort  of  a  handle.  This  is  a 
thin  light  wheel  generally  made 
with  a  circumference  of  about 
24".  The  side  of  the  rim  is  some- 
times graduated  in  inches  by 
eighths.  To  use  it,  the  wheel  is 
placed  lightly  in  contact  with  the 
line  or  object  which  it  is  wished 
to  measure,  with  the  zero-mark  on 
the  wheel  corresponding  to  the  point  from  which 
the  measurement  is  started.  The  wheel  is  then 


FlG- 


46  FORGE-PRACTICE. 

pushed  along  the  surface  following  the  line  to  be 
measured,  with  just  pressure  enough  to  make  it 
revolve.  By  counting  the  revolutions  made  and 
setting  the  pointer  or  making  a  mark  on  the  wheel 
to  correspond  to  the  end  of  the  line  when  it  is 
reached,  it  is  an  easy  matter  to  push  the  wheel  over 
a  straight  line  for  the  same  number  of  revolutions 
and  part  of  a  revolution  as  shown  by  the  pointer 
and  measure  the  length.  If  the  wheel  is  gradu- 
ated, the  length  run  over  can  of  course  be  read 
directly  from  the  figures  on  the  side  of  the  wheel. 

Calculating  Stock  for  Circles. — On  circles  and  parts 
of  circles,  the  length  may  be  calculated  mathe- 
matically, and  in  the  majority  of  cases  this  is  prob- 
ably the  easiest  and  most  accurate  method.  This 
is  done  in  the  following  way :  The  circumference,  or 
distance  around  a  circle,  is  equal  to  the  diameter 
multiplied  by  3^  (or  more  accurately,  3.1416). 

As  an  illustration,  the  length  of  stock  required  to 
bend  up  the  ring  in  Fig.  56  is  calculated  as  follows: 
The  inside  diameter  of  the  ring  is  6"  and  the 
stock  i"  in  diameter.     The  length  must,  of  course, 
be  measured  along  the  center 
of   the    stock,    as    shown   by 
the    dotted    line.     It    is    the 
diameter  of  this  circle,  made 
by   the   dotted  line,    that   is 
used      for      calculating      the 
length    of    stock;      and     for 
convenience     this     may     be 
FIG.  56.  called  the    "calculating"    di- 

ameter, shown  by  C  in  Fig.  56. 


CALCULATION    OF    STOCK    FOR   BENT    SHAPES.  47 

The  length  of  this  calculating  diameter  is  equal 
to  the  inside  diameter  of  the  ring  with  one-half  the 
thickness  of  stock  added  at  each  end,  and  in  this 
case  would  be  i"  +  6"  +  i"=  7"- 

The  length  of  stock  required  to  make  the  ring 
would  be  7"X3f  =  22";  or,  in  other  words,  to  find 
the  length  of  stock  required  to  make  a  ring,  multi- 
ply the  diameter  of  the  ring,  measured  from  center 
to  center  of  the  stock,  by  3^. 

Calculating  Stock  for  "  U's." — Some  shapes  may 
be  divided  up  into  straight  lines  and  parts  of  circles 
and  then  easily  calculated.  Thus  U — ajg" — »j 
the  U  shape  in  Fig.  57  may  be 
divided  into  two  straight  sides  and 
a  half -circle  end.  The  end  is  half  of 
a  circle  having  an  outside  diameter 
of  3J".  The  calculating  diameter  of 
this  circle  would  be  3",  and  the 
length  of  stock  required  for  an  entire  FIG.  57. 

circle  this  size  3X31  =  9*,  which  for  convenience 
we  may  call  Q|  ",  as  this  is  near  enough  for  ordinary 
work.  As  the  forging  calls  for  only  half  a  circle, 
the  length  needed  would  be  gf"  -j-i  =  4^J". 

As  the  circle  is  3^"  outside  diameter,  half  of  this 
diameter,  or  if",  must  be  taken  from  the  total 
length  of  the  U  to  give  the  length  of  the  straight 
part  of  the  sides ;  in  other  words,  the  distance  from 
the  line  A  to  the  extreme  end  of  the  U  is  half  the 
diameter  of  the  circle,  or  if".  This  leaves  the 
straight  sides  each  4^"  long,  or  a  total  length  for 
both  of  8J".  The  total  stock  required  for  the 
forging  would  be : 


48 


FORGE-PRACTICE. 


Total 


Length  stock  for  sides 8J" 

"       V    end '.  .  ..    4iJ" 

-        "       "     forging 13-^". 


Link. — As  another  example,  take  the  link  shown 
in  Fig.  58.     This  may  be  divided  into  the  two  semi- 
circles at  the  ends  and  the 
two  straight  sides.     Calcu- 
lating   as    always  through 
the   center    of    the   stock, 
there  are  the   two  straight 
sides  2"  long,  or  4",  and  the 
FlG-  58-  two    semicircular    ends,   or 

one  complete  circle  for  the  two  ends.  The  length 
required  for  these  two  ends  would  be  ii"X3|"  = 
f  f "  =  4i",  or,  nearly  enough,  4}$".  The  total  length 


of  the  stock  would  be  4"  + 


to  which 


must  be  added  a  slight  amount  for  the  weld. 

Double  Link. — The  double  link  in  Fig.  59  is  an- 
other example  of  stock  calculation.  Here  there 
are  two  complete  circles  each  hav- 
ing an  inside  diameter  of  f  ",  and, 
as  they  are  made  of  \"  stock,  a 
1 '  calculating ' '  diameter  of  i " .  The 
length  of  stock  required  for  one  side 
would  be  3.1416"  X  i"  =  3.i4i6", 
and  the  total  length  for  complete 
links  3. 1416" X 2"- 6. 2832",  which  is  about  6J".. 

As  a  general  rule  it  is  much  easier  to  make  the 
calculations  with  decimals  as  above  and  then 
reduce  these  decimals  to  eighths,  sixteenths,  etc. 


FIG.  59. 


CALCULATION   OF    STOCK    FOR    BENT    SHAPES.  49 

Use  of  Tables. — To  aid  in  reduction  a  table  of 
decimal  equivalents  is  given  on  p.  249.  By  using 
this  table  it  is  only  necessary  to  find  the  decimal 
result  and  select  the  nearest  sixteenth  in  the  table. 
It  is  generally  sufficiently  accurate  to  take  the 
nearest  sixteenth. 

A  table  of  circumferences  of  circles  is  also  given; 
and  by  looking  up  the  diameter  of  any  circle  the 
circumference  may  be  found  opposite. 

To  illustrate,  suppose  it  is  necessary  to  find  the 
amount  of  stock  required  to  make  a  ring  6"  inside 
diameter  out  of  f "  round  stock.  This  would  make 
the  calculating  diameter  of  the  ring  6f . 

In  the  table  of  circumferences  and  areas  of  circles 
opposite  a  diameter  6}  is  found  the  circumference 
21.206.  In  the  table  of  decimal  equivalents  it  will 
be  seen  that  -&-  is  the  nearest  sixteenth  to  the  deci- 

i  o 

mal  .206;  thus  the  amount  of  stock  required  is 
2i-ta6-".  This  of  course  makes  no  allowance  for 
welding. 

Allowance  for  Welding.- — Some  allowance  must 
always  be  made  for  welding,  but  the  exact  amount 
is  very  hard  to  determine,  as  it  depends  on  how 
carefully  the  iron  is  heated  and  how  many  heats 
are  taken  to  make  the  weld. 

The  only  stock  which  is  really  lost  in  welding, 
and  consequently  the  only  waste  which  has  to  be 
allowed  for,  is  the  amount  which  is  burned  off  or 
lost  in  scale  when  heating  the  iron. 

Of  course  when  preparing  for  the  weld  the  ends 
of  the  piece  are  upset  and  the  work  consequently 
shortened,  and  the  pieces  are  still  farther  shortened 


50  FORGE-PRACTICE. 

by  overlapping  the  ends  in  making  the  weld;  but 
all  this  material  is  afterward  hammered  back  into 
shape  so  that  no  loss  occurs  here  at  all,  except  of 
course  the  loss  from  scaling. 

A  skilled  workman  requires  a  very  small  allow- 
ance for  waste  in  welding,  in  fact  sometimes  none 
at  all;  but  by  the  beginners  an  allowance  should 
always  be  made. 

No  rules  can  be  given;  but  as  a  rough  guide  on 
small  work,  a  length  of  stock  equal  to  from  one- 
fourth  to  three-fourths  the  thickness  of  the  bar  will 
probably  be  about  right  for  waste  on  rings,  etc. 
When  making  straight  welds,  when  possible  it  is 
better  to  allow  a  little  more  than  is  necessary  and 
trim  off  the  extra  stock  from  the  end  of  the  finished 
piece. 

Work  of  this  kind  should  be  watched  very  closely 
and  the  stock  measured  before  and  after  welding  in 
order  to  determine  exactly  how  much  stock  is  lost 
in  welding.  In  this  way  an  accurate  knowledge  is 
soon  obtained  of  the  proper  allowance  for  waste. 


CHAPTER  IV. 

UPSETTING,    DRAWING  OUT,    AND   BENDING. 

Drawing  Out. — When  a  piece  of  metal  is  worked 
out,  either  by  pounding  or  otherwise,  in  such  a  way 
that  the  length  is  increased,  and  either  the  width  or 
thickness  reduced,  we  say  that  the  metal  is  being 
"  drawn  out,"  and  the  operation  is  known  as  "  draw- 
ing out." 

It  is  always  best  when  drawing  out  to  heat  the 
metal  to  as  high  a  heat  as  it  will  stand  without 
injury.  Work  can  sometimes  be  drawn  out  much 
faster  by  working  over  the  horn  of  the  anvil  than  on 
the  face,  the  reason  being  this:  when  a  piece  of 
iron  is  laid  flat  on  the  anvil  face  and  hit  a  blow  with 
the  hammer,  it  flattens  out  and  spreads  both  length- 
wise and  crosswise,  making  the  piece  longer  and 
wider.  The  piece  is  not  wanted  wider,  however, 
but  only  longer,  so  it  is  necessary  to  turn  it  on  edge 
and  strike  it  in  this  position,  when  it  will  again  in- 
crease in  length  and  also  in  thickness,  and  will  have 
to  be  thinned  out  again.  A  good  deal  of  work  thus 
goes  to  either  increasing  the  width  or  thickness, 
which  is  not  wanted  increased;  consequently  this 
work  and  the  work  required  to  again  thin  the  forg- 
ing are  lost.  In  other  words,  when  drawing  out 
iron  on  the  face  of  the  anvil  the  force  of  the  blow  is 


52  FORGE-PRACTICE. 

expended  in  forcing  the  iron  sidewise  as  well  as 
lengthwise,  and  the  work  used  in  forcing  the  iron 
sidewise  is  lost.  Thus  only  about  one  half  the 
force  of  the  blow  is  really  used  to  do  the  work 
wanted. 

Suppose  the  iron  be  placed  on  the  horn  of  the 


FIG.  60. 

anvil,  as  shown  in  Fig.  60,  and  hit  with  the  hammer 
as  before.  The  iron  will  still  spread  out  sidewise  a 
little,  but  not  nearly  as  much  as  before  and  will 
lengthen  out  very  much  more.  The  horn  in  this 
case  acts  as  sort  of  a  blunt  wedge,  forcing  out  the 
metal  in  the  direction  of  the  arrow,  and  the  force  of 
the  blow  is  used  almost  entirely  in  lengthening  the 
work. 

Fullers  may  be  used  for  the  same  purpose,  and 
the  work  held  either  on  the  horn  or  the  face  of  the 
anvil. 

Drawing  Out  and  Pointing  Round  Stock. — When 
drawing  out  or  pointing  round  stock  it  should  always 
be  first  forged  down  square  to  the  required  size  and 
then,  in  as  few  blows  as  possible,  rounded  up. 

Fig.  6 1  illustrates  the  different  steps  in  drawing 
out  round  iron  to  a  smaller  size.  A  is  the  original 


UPSETTING,    DRAWING   OUT,    AND    BENDING. 


53 


bar,  B  is  the  first  step,  C  is  the  next,  when  the  iron 
is  forged  octagonal,  and  the  last  step  is  shown  at  D, 


FIG.  61. 

where  the  iron  is  finished  tip  round.  In  drawing 
out  a  piece  of  round  iron  it  should  first  be  forged 
like  B,  then  like  C,  and  lastly  finished  like  D. 

As  an  example:  Suppose  part  of  a  bar  of  J" 
round  stock  is  to  be  drawn  down  to  f "  in  diameter. 
Instead  of  pounding  it  down  round  and  round  until 
the  J"  diameter  is  reached,  the  part  to  be  drawn  out 
should  be  forged  perfectly  square  and  this  drawn 
down  to  f  ",  keeping  it  as  nearly  square  as  possible 
all  the  time. 

The  corners  of  the  square  are  forged  off,  making 
an  octagon,  and,  last  of  all,  the  work  is  rounded  up. 
This  prevents  the  metal  from  splitting,  as  it  is  very 
liable  to  do  if  worked  round  and  round. 


FIG.  63. 

The  reason  for  the  above  is  as  follows:    Suppose 
Fig.  62  represents  the  cross-section  of  a  round  bar 


54  FORGE-PRACTICE. 

as  it  is  being  hit  on  the  upper  side.  The  arrows 
indicate  the  flow  of  the  metal — that  is,  it  is  forged 
together  at  A  A  and  apart  at  BB.  Now,  as  the  bar 
is  turned  and  the  hammering  continued,  the  out- 
side metal  is  forced  away  from  the  center,  which 
may,  at  last,  give  way  and  form  a  crack;  and  by 
the  time  the  bar  is  of  the  required  size,  if  cut,  it 
would  probably  look  something  like  Fig.  63. 

The  same  precaution  must  be  taken  when  forging 
any  shaped  stock  down  to  a  round  or  conical  point. 
The  point  must  first  be  made  square  and  then 
rounded  up  by  the  method  given  above.  If  this  is 
not  done  the  point  is  almost  sure  to  split. 

Squaring  Up  Work.  —  A  common  difficulty  met 
with  in  all  drawing  out,  or  in  fact  in  all  work  which 
must  be  hammered  up  square,  is  the  liability  of  the 
bar  to  forge  into  a  diamond  shape,  or  to  have  one 
corner  projecting  out  too  far.  If  a  section  be  cut 
through  a  bar  misshaped  in  this  way,  at  right  angles 
to  its  length,  instead  of  being  a  square  or  rectangle, 
the  shape  will  appear  something  like  one  of  the  out- 
lines in  Fig.  64. 


FIG.  64.  FIG.  65. 

To  remedy  this  and  square  up  the  bad  corners, 
lay  the  bar  across  the  anvil  and  strike  upon  the 
projecting  corners  as  shown  in  Fig.  65,  striking  in 
such  a  way  as  to  force  the  extra  metal  back  into  the 


UPSETTING,    DRAWING   OUT,    AND    BENDING.  55 

body  of  the  bar,  gradually  squaring  it  off.  Just  as 
the  hammer  strikes  the  metal  it  should  be  given  a 
sort  of  a  sliding  motion,  as  indicated  by  the  arrow. 

No  attempt  should  be  made  to  square  up  a  corner 
of  this  kind  by  simply  striking  squarely  down  upon 
the  work.  The  hammering  should  all  be  done  in 
such  a  way  as  to  force  the  metal  back  into  the  bar 
and  away  from  the  corner. 

Upsetting. — When  a  piece  of  metal  is  worked  in 
such  a  way  that  its  length  is  shortened,  and  either 
or  both  its  thickness  and  width  increased,  the  piece 
is  said  to  be  upset;  and  the  operation  is  known  as 
upsetting. 

There  are  several  ways  of  upsetting,  the  method 
depending  mostly  on  the  shape  the  work  is  in.  With 
short  pieces  the  work  is  generally  stood  on  end  on 
the  anvil  and  the  blow  struck  directly  on  the  upper 
end.  The  work  should  always  be  kept  straight; 
after  a  few  blows  it  will  probably  start  to  bend  and 
must  then  be  straightened  before  more  upsetting  is 
done. 

If  one  part  only  of  a  piece  is  to  be  upset,  then  the 
heat  must  be  confined  to  that  part,  as  the  part  of 
the  work  which  is  hottest  will  be  upset  the  most. 

When  upsetting  a  short  piece  for  its  entire  length, 
it  will  sometimes  work  up  like  Fig.  66.  This  may 
be  due  to  two  causes:  either  the  ends  were  hotter 
than  the  center  or  the  blows  of  the  hammer  were 
too  light.  To  bring  a  piece  of  this  sort  to  uniform 
size  throughout,  it  should  be  heated  to  a  higher  heat 
in  the  center  and  upset  with  heavy  blows.  If  the 
work  is  very  short  it  is  not  always  convenient  to 


56  FORGE-PRACTICE. 

confine  the  heat  to  the  central  part;  in  such  a  case, 
the  piece  may  be  heated  all  over,  seized  by  the  tongs 
in  the  middle  and  the  ends  cooled,  one  at  a  time,  in 
the  water-bucket. 


FIG.  66.  FIG.  67. 

When  light  blows  are  used  the  effect  of  the  blow 
does  not  reach  the  middle  of  the  work,  and  conse- 
quently the  upsetting  is  only  done  on  the  ends. 

The  effect  of  good  heating  and  heavy  blows  is 
shown  in  Fig.  67.  With  a  heavy  blow  the  work  is 
upset  more  in  the  middle  and  less  on  the  ends. 

To  bring  a  piece  of  this  kind  to  uniform  size 
throughout,  one  end  should  be  heated  and  upset 
and  then  the  other  end  treated  in  the  same  way, 
confining  the  heat  each  time  as  much  as  possible 
to  the  ends. 

Long  work  may  be  upset  by  laying  it  across  the 
face  of  the  anvil,  letting  the  heated  end  extend  two 
or  three  inches  over  the  edge,  the  upsetting  being 
done  by  striking  against  this  end  with  the  hammer 
or  sledge.  If  the  work  is  heavy  the  weight  will 
offer  enough  resistance  to  the  blow  to  prevent  the 
piece  from  sliding  back  too  far  at  each  blow;  but 
with  lighter  pieces  it  may  be  necessary  to  "back 
up"  the  work  by  holding  a  sledge  against  the  un- 
heated  end. 


UPSETTING,    DRAWING   OUT,    AND   BENDING.  57 

Another  way  of  upsetting  the  ends  of  a  heavy 
piece  is  to  ' '  ram ' '  the  heated  end  against  the  side  of 
the  anvil  by  swinging  the  work  back  and  forth  hori- 
zontally and  striking  it  against  the  side  of  the  anvil. 
The  weight  of  the  piece  in  this  case  takes  the  place 
of  the  hammer  and  does  the  upsetting. 

Heavy  pieces  are  sometimes  upset  by  lifting  them 
up  and  dropping  or  driving  them  down  on  the  face 
of  the  anvil  or  against  a  heavy  block  of  iron  resting 
on  the  floor.  Heavy  cast-iron  plates  are  sometimes 
set  in  the  floor  for  this  purpose,  and  are  called 
' '  upsetting-plates . ' ' 

Fig.  68  shows  the  effect  of  the  blows  when  upset- 
ting the  end  of  a  bar.  The  lower  piece  has  been 
properly  heated  and  upset  with 
heavy  blows,  while  the  other 
piece  shows  the  effect  of  light 
blows.  This  last  shape  may  also 
be  caused  by  having  the  extreme 
end  at  a  higher  heat  than  the  rest 
of  the  part  to  be  upset.  FlG-  68- 

Punching. — There  are  two  kinds  of  punches  used 
for  making  holes  in  hot  metal— the  straight  hand- 
punch,  used  with  a  hand-hammer,  and  the  punch 
made  from  heavier  stock  and  provided  with  a 
handle,  used  with  a  sledge-hammer. 

Punches  should,  of  course,  be  made  of  tool-steel. 

For  punching  small  holes  in  thin  iron  a  hand- 
punch  is  ordinarily  used.  This  is  simply  a  bar  of 
round  or  octagonal  steel,  eight  or  ten  inches  long, 
with  the  end  forged  down  tapering,  and  the  extreme 
end  the  same  shape,  but  slightly  smaller  than  the 


FORGE-PRACTICE. 


hole  which  is  to  be  punched.  Such  a  punch  is 
shown  in  Fig.  69.  The  punch  should  taper  uni- 
formly, and  the  extreme  end  should  be  perfectly 
square  across,  not  in  the  least  rounding. 


FIG.  69. 


FIG.  70. 


For  heavier  and  faster  work  with  a  helper,  a 
punch  like  Fig.  70  is  used.  This  is  driven  into  the 
work  with  a  sledge-hammer. 

A,  B,  and  C,  in  Fig.  71,  show  the  different  steps 
in  punching  a  clean  hole  through  a  piece  of  hot  iron. 


FIG.  71. 

The  punch  is  first  driven  about  half-way  through 
the  bar  while  the  work  is  lying  flat  on  the  anvil ; 
this  compresses  the  metal  directly  underneath  the 
punch  and  raises  a  slight  bulge  on  the  opposite  side 
of  the  bar  by  which  the  hole  can  be  readily  located. 
The  piece  is  then  turned  over  and  the  punching 
completed  from  this  side,  the  small  piece,  "A", 
being  driven  completely  through.  This  leaves  a 


UPSETTING,    DRAWING   OUT,   AND   BENDING.  59 

clean  hole ;  while  if  the  punching  were  all  done  from 
one  side,  a  burr,  or  projection,  would  be  raised  on 
the  side  where  the  punch  came  through. 

D  and  E  (Fig.  71)  illustrate  the  effects  of  proper 
and  improper  punching.  If  started  from  one  side 
and  finished  from  the  other  the  hole  will  be  clean 
and  sharp  on  both  sides  of  the  work;  but  if  the 
punching  is  done  from  one  side  only  a  burr  will  be 
raised,  as  shown  at  E,  on  the  side  opposite  to  that 
from  which  the  punching  is  done. 

If  the  piece  is  thick  the  punch  should  be  started, 
then  a  little  powdered  coal  put  in  the  hole,  and  the 
punching  continued.  The  coal  prevents  the  punch 
from  sticking  as  much  as  it  would  without  it. 

Bending. — Bends  may  be  roughly  divided  into  two 
classes — curves  and  angles. 

Angles.  —  In  bending  angles  it  is  nearly  always 
necessary  to  make  the  bend  at  some  definite  point 
on  the  stock.  As  the  measurements  are  much  easier 
made  while  the  stock  is  cold  than  when  hot,  it  is 
best  to  "lay  off"  the  stock  before  heating. 

The  point  at  which  the  bend  is  to  be  made  should 
be  marked  with  a  center  punch — generally  on  the 
edge  of  the  stock,  in  preference  to  the  side. 

Marking  with  a  cold  chisel  should  not  be  done 
unless  done  very  lightly  on  the  edge  of  stock.  If  a 
slight  nick  be  made  on  the  side  of  a  piece  of  stock  to 
be  bent,  and  the  stockbent  at  this  point  with  the 
nick  outside,  the  small  nick  will  expand  and  leave 
quite  a  crack.  If  the  nick  be  on  the  inside,  it  is  apt 
to  start  a  bad  cold  shut  which  may  extend  nearly 
through  the  stock  before  the  bending  is  finished. 


6o 


FORGE-PRACTICE. 


Whenever  convenient,  it  is  generally  easier  to 
bend  in  a  vise,  as  the  piece  may  be  gripped  at  the 
exact  point  where  the  bend  is  wanted. 

When  making  a  bend  over  the  anvil  the  stock 
should  be  laid  flat  on  the  face,  with  the  point  at 


o 


FIG.  72. 

which  the  bend  is  wanted  almost,  but  not  quite,  up 
to  the  outside  edge  of  the  anvil. 

The  bar  should  be  held  down  firmly  on  the  anvil 
by  bearing  down  on  it  with  a  sledge,  so  placed  that 
the  outside  edge  of  the  sledge  is  about  in  line  with 
the  outside  edge  of  the  anvil. 

This  makes  it  possible  to  make  a  short  bend  with 
less  hammering  than  when  the  sledge  is  not  used. 

The  bar  will  pull  over  the  edge  of  the  anvil 
slightly  when  bending. 

Bend   with   Forged   Corner.  —  Brackets   and   other 
/  forgings  are  sometimes  made  with 
the  outside   corner  of  the   bend 
forged   up   square,    as  shown    in 

Fig.  73- 

There     are     several    ways     of 
bending  a  piece   to  finish  in  this 
FIG.  73.  shape. 

One  way  is  to  take  stock  of  the  required  finished 


UPSETTING,    DRAWING    OUT,    AND    BENDING.  6 1 

size  and  bend  the  angle,  forging  the  corner  square 
as  it  is  bent ;  another  is  to  start  with  stock  consid- 
erably thicker  than  the  finished  forging  and  draw 
down  both  ends  to  the  required  finished  thickness, 
leaving  a  thin-pointed  ridge  across  the  bar  at  the 
point  where  the  bend  will  come,  this  ridge  forming 
the  outside  or  square  corner  of  the  angle  where  the 
piece  is  bent ;  or  this  ridge  may  be  formed  by  upset- 
ting before  bending. 

The  process  in  detail  of  the  first  method  men- 
tioned is  as  follows :  The  first  step  is  to  bend  the  bar 
so  that  it  forms  nearly  a  right  angle,  keeping  the 
bend  as  sharp  as  possible,  as  shown  at  A  (Fig.  74). 


FIG.  74. 

This  should  be  done  at  a  high  heat,  as  the  higher 
the  heat  the  easier  it  is  to  bend  the  iron  and  conse- 
quently the  sharper  the  bend. 

Working  the  iron  at  a  good  high  heat,  as  before, 
the  outside  of  the  bend  should  be  forged  into  a 
sharp  corner,  letting  the  blows  come  in  such  a  way 
as  to  force  the  metal  out  where  it  is  wanted,  being 
careful  not  to  let  the  angle  bend  so  that  it  becomes 
less  than  a  right  angle  or  even  equal  to  one.  Fig. 


62  FORGE-PRACTICE. 

74,  B,  shows  the  proper  way  to  strike.  The  arrows 
indicate  the  direction  of  the  blows. 

The  work  should  rest  on  top  of  the  anvil  while 
this  is  being  done,  not  over  one  corner.  If  worked 
over  the  corner,  the  stock  will  be  hammered  too 
thin. 

The  object  in  keeping  the  angle  obtuse  is  this: 
The  metal  at  the  corner  of  the  bend  is  really  being 
upset,  and  the  action  is  somewhat  as  follows:  In 
Fig.  75  is  shown  the  bent  piece  on  the  anvil.  We 
will  suppose  the  blows  come  on  the  part  A  in  the 
direction  indicated  by  the  heavy  arrow.  The 
metal,  being  heated  to  a  high  soft  heat  at  C,  upsets, 
part  of  it  forming  the  sharp  outside  corner  and 
part  flowing  as  shown  by  the  small  arrow  at  C  and 


FIG.  75.  FIG.  76 

making  a  sort  of  fillet  on  the  inside  corner.  If  in 
place  of  having  the  angle  greater  than  90  degrees  it 
had  been  an  acute  angle  (Fig.  76),  the  metal  forced 
downward  by  the  blows  on  A  would  carry  with  it 
part  of  the  metal  on  the  inside  of  the  piece  B,  and 
a  cold  shut  or  crack  would  be  formed  on  the  inside 
of  the  angle.  To  form  a  sound  bend  the  corner 
must  be  forged  at  an  angle  greater  than  a  right 
angle.  When  the  piece  has  been  brought  to  a  sharp 


UPSETTING,    DRAWING    OUT,    AND    BENDING.  63 

corner  the  last  step  is  to  square  up  the  bend  over 
the  corner,  or  edge,  of  the  anvil. 

The  second  way  of  making  the  above  is  to  forge 
a  piece  as  shown  in  Fig.  77, 
where  the  dotted  lines  indi- 
cate the  size  of  the  original 
piece.  This  piece  is  then 
bent  in  such  a  way  that  the 
ridge,  C,  forms  the  outside  FlG-  77- 

sharp  corner  of  the  angle. 

This  ridge  is  sometimes  upset  in  place  of  being 
drawn  out. 

The  first  method  described  is  the  most  satisfac- 
tory. 

Ring-bending. — In  making   a   ring   the    first   step 

of  course  is  to  calculate  and  cut  from  the  bar  the 

proper  amount  of  stock.     The  bend  should  always 

be  started  from  the  end  of  the  piece.     For  ordinary 

rings  up  to  4"  or  5"  in  diameter  the  stock  should 

be  heated  for  about  one-half  its  length.     To  start 

bending,  the  extreme   end  of  the  piece  should  be 

first  bent  over  the  horn  of  the  anvil,  and  the  bar 

should  be  fed  across  the  horn  of  the  anvil  and  bent 

down  as  it  is  pushed  forward.     Do 

^JH     not  strike   directly  on  top   of   the 

^^—^!j      horn,  but  let  the  blows  fall  a  little 

(    J  way  from  it,  as  in  Fig.   78.     This 

FIG  78  bends  the  iron  and  does  not  pound 

it  out  of  shape.      One-half  of   the 

ring  is  bent    in   this  way    and   then   the  part  left 

straight  is  heated.     This  half  is  bent  up  the  same 

as  the  other,  starting  from  the  end  exactly  as  before. 


64 


FORGE-PRACTICE. 


FIG.  79. 


Eye-bending.  —  The  first  step  in  making  an  eye 
like  Fig.  79  is  to  calculate  the 
amount  of  stock  required  for  the 
bend.  The  amount  required  in  this 
case,  found  by  looking  up  the  circum- 
ference of  a  2"  circle  in  the  table,  is 
7J".  This  distance  should  be  laid  off  by  making 
a  chalk-mark  on  the  face  of  the  anvil  yj"  from  the 
left-hand  end. 

A  piece  of  iron  is  heated  and  laid  on  the  anvil  with 
the  heated  end  on  the  chalk-mark,  the  rest  of  the 
bar  extending  to  the  left.  A  hand-hammer  is  held 
on  the  bar  with  the  edge  of  the  hammer  directly  in 
line  with  the  end  of  the  anvil.  This  measures  off 
7i"  from  the  edge  of  the  hammer  to  the  end  of  the 
bar.  The  bar  is  then  laid  across  the  anvil  bringing 
the  edge  of  the  hammer  exactly  in  line  with  the 
outside  edge  of  the  anvil,  thus  leaving  yj"  project- 
ing over  the  edge.  This  projecting  end  is  bent 
down  until  it  forms  a  right  angle.  The  extreme 
end  of  this  bent  part  is  then  bent  over  the  horn  into 


FIG.  80. 


the  circular  shape  and  the  bending  continued  until 
the  eye  is  formed. 


UPSETTING,   DRAWING    OUT,    AND    BENDING. 


The  same  general  method  as  described  for  bend- 
ing rings  should  be  followed.  The  different  steps 
are  shown  in  Fig.  80. 

If  an  eye  is  too  small  to  close 
up  around  the  horn,  it  may  be 
closed  as  far  as  possible  in 
this  way,  and  then  completely 
closed  over  the  corner  or  on 
the  face  of  the  anvil,  as  shown 
in  Fig.  81. 

Double  Link. — Another  good  FlG-  8l- 

example  of  this  sort  of  bending  is  the  double  link, 
shown  in  Fig.  59. 

The  link  is  started  by  bending  the  stock  in  the 
exact  center,  the  first  step  being  to  bend  a  right 
angle.  This  step,  with  the  succeeding  ones,  is 
shown  in  Fig.  82. 


2nd 


1st 


3rd 


4th 


FIG.  82. 


After  this  piece  has  been  bent  into  a  right  angle, 
the  ring  on  the  end  should  be  bent  in  the  same  way 


66  FORGE-PRACTICE. 

as  an  ordinary  ring ;  excepting  that  all  the  bending 
is  done  from  one  end  of  the  piece,  starting  from  the 
extreme  end  as  usual. 

Twisting. — Fig.  83  shows  the  effects  produced  by 
twisting  stock  of  various  shapes — square,  octagonal, 


FIG.  83. 

and  flat,  the  shapes  being  shown  by  the  cuts  in 
each  case. 

To  twist  work  in  this  way  it  should  be  brought  to 
a  uniform  heat  through  the  length  intended  to 
twist.  When  the  bar  is  properly  heated  it  should 
be  firmly  gripped  with  a  pair  of  tongs,  or  in  a  vise, 
at  the  exact  point  where  the  twist  is  to  commence. 
With  another  pair  of  tongs  the  work  is  taken  hold 
of  where  the  twist  is  to  stop,  and  the  bar  twisted 
through  as  many  turns  as  required.  The  metal 
will  of  course  be  twisted  only  between  the  two  pairs 
of  tongs,  or  between  the  vise  and  the  tongs,  as  the 
case  may  be;  so  care  must  be  used  in  taking  hold 
of  the  bar  or  the  twist  will  be  made  at  the  wrong 
points. 

The  heat  must  be  the  same  throughout  the  part 
to  be  twisted.  If  one  part  is  hotter  than  another, 


UPSETTING,  DRAWING    OUT,    AND   BENDING.  67 

this  hotter  part,  being  softer,  will  twist  more  easily, 
and  the  twist  will  not  be  uniform.  If  one  end  of 
the  bar  is  wanted  more  tightly  twisted  than  the 
other,  the  heat  should  be  so  regulated  that  the  part 
is  heated  hottest  that  is  wanted  tightest  twisted; 
the  heat  gradually  shading  off  into  the  parts  wanted 
more  loosely  twisted. 

Reverse  Twisting.  —  The  effect    shown   in  Fig.  84 
is  produced  by  reversing  the  direction  of  twisting. 


FIG.  84. 

A  square  bar  is  heated  and  twisted  enough  to 
give  the  desired  angle.  It  is  then  cooled,  in  as 
sharp  a  line  as  possible,  as  far  as  B,  and  twisted 
back  in  the  opposite  direction.  It  is  again  heated, 
cooled  up  to  A,  and  twisted  in  the  first  direction ; 
and  this  operation  is  continued  until  the  twist  is  of 
the  desired  length. 


CHAPTER  V. 

SIMPLE   FORGED   WORK. 

Twisted  Gate-hook. — This  description  answers,  of 
course,  not  only  for  this  particular  piece,  but  for 
others *of  a  like  nature. 

Fig.  85  shows  the  hook  to  be  made.  To  start 
with,  it  must  be  determined  what  length  of  stock, 


FIG.  85. 

after  it  is  forged  to  proper  size,  will  be  required  to 
bend  up  the  ends. 

The  length  of  straight  stock  necessary  should,  of 
course,  be  measured  through  the  center  of  the 
stock  on  the  dotted  lines  in  the  figure.  To  do  this 
lay  out  the  work  full  size,  and  lay  a  string  or  thin 
piece  of  soft  wire  upon  the  lines  to  be  measured. 
It  is  then  a  very  easy  matter  to  straighten  out  the 
wire  or  string,  and  measure  the  exact  length  re- 
quired. If  the  drawing  is  not  made  full  size,  an 
accurate  sketch  may  be  made  on  a  board,  or  other 
flat  surface,  and  the  length  measured  from  this. 

68 


SIMPLE  FORGED  WORK.  69 

The  hook  as  above  will  require   about  2\"  length 
for  stock;  the  eye,  about  2%"  '. 
The  first  step  would  be  like  Fig.  86. 


4     -•**-- 

FIG.  86. 


After  cutting  the  piece  of  -f$"  square  stock,  start 
the  forging  by  drawing  out  the  end,  starting  from 
the  end  and  working  back  into  the  stock  until  a 
piece  is  forged  out  2f"  long  and  J"  in  diameter. 
Now  work  in  the  shoulder  with  the  set  -hammer  in 
the  following  way: 

Forming  Shoulders:  Both  Sides  —  One  Side.  —  Place 
the  piece  on  the  anvil  in  such  a  position  that 
the  point  where  the  shoulder  is  wanted  comes 
exactly  on  the  nearest  edge  of  the  anvil.  Place 
the  set-hammer  on  top  of  the  piece  in  such  a  way 
that  its  edge  comes  directly  in  line  with  the  edge  of 
the  anvil  (Fig.  87).  Do  not  place  the  piece  like 


FIG   87.  FIG   88. 

Fig.  88,  or  the  result  will  be  as  shown — a  shoulder 
on  one  side  only.  As  the  shoulder  is  worked  in  the 
piece  should  be  turned  continually,  or  the  shoulder 


7°  FORGE-PRACTICE. 

will  work  in  faster  on  one  side  than  on  the  other. 
Always  be  careful  to  keep  the  shoulder  exactly  even 
with  the  edge  of  the  anvil. 

When  the  piece  is  formed  in  the  proper  shape  on 
one  end,  start  the  second  shoulder  4"  from  the  first, 
and  finish  like  Fig.  86.  Bend  the  eye  and  then  the 
hook;  and,  lastly,  put  the  twist  in  the  center. 
Make  the  twist  as  follows: 

First  make  a  chalk-mark  on  the  jaws  of  the  vise, 
so  that  when  the  end  of  the  hook  is  even  with  the 
mark  the  edge  of  the  vise  will  be  where  one  end  of 
the  twist  should  come.     Heat  the  part  to  be  twisted 
to  an  even  yellow  heat  (be  sure 
that  it  is  heated  evenly) ;  place 
*   it  in  a  vise  quickly,  with  the  end 
even  with  the  mark;   grasp  the 
piece  with  the  tongs,  leaving  the 
FlG  g  distance  between  the  tongs  and 

vise  equal  to  the  length  of  twist 
(Fig.  89) ;   and  twist  it  around  one  complete  turn. 

The  eye  should  be  bent  as  described  before,  and 
the  hook  bent  in  the  same  general  way  as  the  eye. 

Grab-hooks. — This  is  the  name  given  to  a  kind 
of  hooks  used  on  chains,  and  made  for  grabbing  or 
hooking  over  the  chain.  The  hook  is  so  shaped  that 
the  throat,  or  opening,  is  large  enough  to  slip  eas- 
ily over  a  link  turned  edgewise,  but  too  narrow  to 
slip  down  off  this  link  on  to  the  next  one,  which,  of 
course,  passes  through  the  first  link  at  right  angles 
to  it. 

Grab-hooks  are  made  in  a  variety  of  ways,  one  of 
vhich  is  given  below  in  detail. 


SIMPLE   FORGED    WORK. 


71 


Fig.  90  will  serve  as  an  example.  To  forge  this, 
use  a  bar  of  round  iron  large  enough  in  section  to 
form  the  heavy  part  of  the  hook.  This  bar  should 
first  be  slightly  upset,  either  by  ramming  or  ham- 
mering, for  a  short  distance  from  the  end,  and  then 
flattened  out  like  Fig.  9 1 . 


FIG.  90. 


FIG.  92. 


FIG.  93. 


The  next  step  is  to  round  up  the  part  for  the  eye, 
as  shown  in  Fig.  92,  by  forming  it  over  the  corner  of 
the  anvil  as  indicated  in  Fig.  93.  The  eye  should 
be  forged  as  nearly  round  as  possible,  and  then 
punched. 

Particular  attention  should  be  paid  to  this  point. 
If  the  eye  is  not  properly  rounded  before  punching, 
it  is  difficult  to  correct  the  shape  afterward. 

After  punching,  the  inside  corners  of  the  hole  are 
rounded  off  over  the  horn  of  the  anvil  in  the  man- 
ner shown  in  Fig.  94.  Fig.  95  shows  the  appear- 
ance of  a  section  of  the  eye  as  left  by  the  punch. 
When  the  eye  is  finished  it  should  appear  as  though 
bent  up  from  round  iron — that  is,  all  the  square 
corners  should  be  rounded  off  as  shown  in  Fig.  96. 

When  the  eye  is  completed  the  body  of  the  hook 


72  FORGE-PRACTICE. 

should  be  drawn  out  straight,  forged  to  size,  and 
then  bent  into   shape.     Care  should  be  taken  to 


S, 

FIG.  94.  FIG.  95.      FIG.  96 

keep  the  hook  thickest  around  the  bottom  of  the 
bend. 

As  the  stock  is  entirely  formed  before  bending, 
the  length  of  the  straight  piece  must  be  carefully 

|« _A ,j     measured,    as  indicated 

(^___  ]^>     at   A    (Fig.    97),  where 

the  piece  is  shown  ready 
FlG'  97'  for  bending.     To  deter- 

mine the  required  length  the  drawing  or  sample 
should  be  measured  with  a  string  or  piece  of  flexible 
wire,  measuring  along  the  center  of  the  stock,  from 
the  extreme  point  to  the  center  of  the  eye. 

The  weakest  point  of  almost  any  hook  is  in  the 
bottom  bend.  When  the  hook  is  strained  there  is 
a  tendency  for  it  to  straighten  out  and  take  the 
shape  shown  by  the  dotted  lines  in  Fig.  90.  To 
avoid  this  the  bottom  of  the  hook  must  be  kept  as 
thick  as  possible  along  the  line  of  strain,  which  is 
shown  by  the  line  drawn  through  the  eye.  A  good 
shape  for  this  lower  bend  is  shown  in  the  sketch, 
where  it  will  be  noticed  that  the  bar  has  been  ham- 
mered a  little  thinner  in  ordrr  to  increase  the  thick- 
ness of  the  metal  in  the  direction  of  the  line  of 
strain. 


SIMPLE  FORGED  WORK.  73 

The  part  of  the  hook  most  liable  to  bend  under  a 
load  is  the  part  lying  between  the  points  marked 
/and /in  Fig.  102. 

Another  style  of  grab-hook  is  shown  in  Fig.  98, 


FIG.  98. 

which  shows  the  finished  hook  and  also  the  straight 
piece  ready  for  bending. 

The  forming  will  need  no  particular  description. 
The  hook  shown  is  forged  about  J"  thick ;  the  out- 
side edge  around  the  curve  being  thinned  out  to 
about  |",  in  order  to  give  greater  stiffness  in  the 
direction  of  the  strain. 

Stock  about  }"  X  i"  is  used. 

A  very  convenient  way  to  start  the  eye  for  a  hook 
of  this  kind,  or  in  fact  almost  any  forged  eye,  is 
shown  in  Fig.  99.  Two  fullers,  top  and  bottom, 
are  used,  and  the  work  shaped  as  shown.  The  bar 
should  be  turned,  edge  for  edge,  between  every  few 
blows,  if  the  grooves  are  wanted  of  the  same  depth. 
After  cutting  the  grooves  the  edge  is  shaped  the 
same  as  described  above. 

A  grab-hook,  sometimes  used  on  logging-chains, 
is  shown  in  Fig.  100.  This  is  forged  from  square 


74  FORGE-PRACTICE. 

stock  by  flattening  and  forming  one  end  into  an  eye 
and  pointing  the  other  end;  after  which  the  hook 
is  bent  into  shape. 


FIG.  99.  FIG.  ioo 

Welded  Eye-hooks.  —  Hooks  sometimes  have  the 
eye  made  by  welding  instead  of  forging  from  the 
solid  stock.  Such  a  hook  is  shown  in  Fig.  101, 


FIG.  ioi. 

which  also  shows  the  stock  scarfed  and  bent  into 
shape  ready  for  closing  up  the  eye  for  the  weld,  and 
also  the  eye  ready  for  welding.  Before  heating  for 
the  weld,  the  eye  should  be  closed,  and  stock  at  the 
end  be  bent  close  together.  The  scarf  should  be 
pointed  the  same  as  for  any  other  round  weld. 


SIMPLE   FORGED   WORK. 


75 


This  sort  of  eye  is  not  as  strong  as  a  forged  eye 
of  the  same  size  ;  but  is  usually  as  strong  as  the  rest 
of  the  hook,  as  the  eye  is  generally  considerably 
stronger  than  any  other  part. 

Hoisting-hooks.  —  A  widely  accepted  shape  for 
hoisting-hooks,  used  on 
cranes,  etc.,  is  shown  in 
Fig.  102.  The  shape  and 
formula  are  given  by  Henry 
R.  Town,  in  his  Treatise  on 
Cranes. 

T  =  working  load  in  tons 
of  2000  Ibs. 

A  =  diameter     of     round 
stock  used  to  form  hook. 

The  size  of  stock  to  use 
for  a  hook  to  carry  any 
particular  load  is  given  below.  The  capacity  of 
the  hook,  in  tons,  is  given  in  the  upper  line  —  the 
figures  in  the  lower  line,  directly  under  any  particu- 
lar load  in  the  upper  line,  giving  the  size  of  bar 
required  to  form  a  hook  to  be  used  at  that  load. 


FIG.  102. 


=i     J 


1}     2      3 

li       If       I 


4568     10 

2       2j      2i      2j      3i 


The  other  dimensions  of  the  hook  are  found  by 
the  following  formula,  all  the  dimensions  being  in 
inches  : 

D=   .sT  +1.25 

E=    .647+1.6 

F=   -33T+   .85 


76  FORGE-PRACTICE. 


G= 

0=    .363T+.66 

Q=    .64T+i.6 

H=i.oSA 


Af=    .855-.  16 
C7=    .S66A 

To  illustrate  the  use  of  the  table,  suppose  a  hook 
is  wanted  to  raise  a  load  of  500  Ibs. 

In  the  line  marked  T  in  the  table  are  found  the 
figures  J,  denoting  a  load  of  one-quarter  of  a  ton,  or 
500  Ibs.  Under  this  are  the  figures  |J-,  giving  the 
size  stock  required  to  shape  the  hook. 

The  different  dimensions  of  the  hook  would  be 
found  as  follows  : 


=.  64X7,  +  1.6"  =1.76  ^iV/'  about. 
=i.o8A  =  i.o8X11/13=.74   =V4  about. 


When  reducing  the  decimals,  the  dimensions 
which  have  to  do  only  with  the  bending  of  the  hook, 
that  is,  the  opening,  the  length,  the  length  of  point, 
etc.,  may  be  taken  as  the  nearest  i6th,  but  these 
dimensions  for  flattening  should  be  reduced  to  the 
nearest  32d  on  small  hooks. 


SIMPLE    FORGED    WORK.  77 

The  complete  dimensions  for  the  hook  in  ques- 
tion, 1000  Ibs.  capacity,  would  be  as  follows : 


D-i1/,"          G=i"  #='//'  L="/ 

E=i3//'          0=   •//'  /- 

F=  15/16"      Q=iaA"         7='V 

^=25/32"         I/-1/,.1 


^/ 

32 


," 


Bolts. — Bolts  are  made  by  two  methods,  upset- 
ting and  welding.  The  first  method  is  the  more 
common,  particularly  on  small  bolts,  where  it  is 
nearly  always  used,  the  stock  being  upset  to 
form  the  head.  In  the  second  method  the  head  is 
formed  by  welding  a  ring  of  stock  around  the  stem. 

An  upset  head  is  stronger  than  a  welded  head, 
provided  they  are  both  equally  well  made. 

The  size  of  the  bolt  is  always  given  as  the  diame- 
ter and  length  of  the  shank,  or  stem.  Thus,  a 
\"  bolt,  6"  long,  means  a  bolt  having  a  shank  \"  in 
diameter,  and  6"  long  from  the  under  side  of  the 
head  to  the  end. 

Dimensions  of  bolt-heads  are  determined  from 
the  diameter  of  the  shank,  and  should  always  be 
the  same  size  for  the  same  diameter,  being  inde- 
pendent of  the  length. 

The  diameter  and  thickness  of  the  head  are  meas- 
ured as  shown  in  Fig.  103. 

The  dimensions  of  both  square  and  hexagonal 
heads  are  as  follows: 

D=  diameter  of  head  across  the  flats  (short 
diameter). 

T  =  thickness  of  head. 

5  =  diameter  of  shank  of  bolt. 


FORGE-PRACTICE. 


For  a  2"  bolt  the  dimensions  would  be  calcu- 
lated as  follows : 

Diameter   of  head  would    equal    ii"X2"  +  J"  = 

*»!/   " 

3    /8      • 

Thickness  of  head  would  be  2". 

These  are  dimensions  for  rough  or  unfinished 
heads;  each  dimension  of  a  finished  head  is  Y1B'; 
less  than  the  same  dimension  of  the  rough  head. 


FIG.  103. 

Bolts  generally  have  the  top  corners  of  the  head 
rounded  or  chamfered  off  (Fig.  103).  This  can 
be  done  with  a  hand-hammer,  or  with  a  cupping- 


FIG.  104. 


FIG.  105. 

tool  (Fig.  104),  which  is  simply  a  set-hammer  with 
the  bottom  face  hollowed  out  into  a  bowl  or  cup 
shape. 


SIMPLE  FORGED  WORK.  79 

For  making  bolts  one  special  tool  is  required, 
the  heading-tool.  This  is  commonly  made  some- 
thing the  shape  of  Fig.  105,  although  for  a  "  hurry- 
up"  bolt  sometimes  any  flat  strip  of  iron  with  a 
hole  punched  the  proper  size  to  admit  the  stem  of 
the  bolt  can  be  used. 

When  in  use  this  tool  is  placed  on  the  anvil 
directly  over  the  square  hardie-hole,  the  stem  of 
the  bolt  projecting  down  through  the  heading-tool 
and  hardie-hole  while  the  head  is  being  forged  on 
the  bolt. 

This  heading-tool  is  made  with  one  side  of  the 
head  flush  with  the  handle,  the  other  side  project- 
ing a  quarter  of  an  inch  or  so  above  it.  The  tool 
should  always  be  used  with  the  flat  side  on  the  anvil. 

Upset-head  Bolt. — An  upset  head  is  made  as  fol- 
lows :  The  stock  is  first  heated  to  a  high  heat  for  a 
short  distance  at  the  end,  and  upset  as  shown  at 
Fig.  1 06 .  The  bolt  is  then  dropped 
through  the  heading  tool,  the  up- 
set  portion  projecting  above.  This 
upset  part  is  then  flattened  down 
on  the  tool  as  shown  at  B,  and 
forged  square  or  hexagonal  on  the 
anvil.  FlG-  Io6- 

The  hole  in  the  heading-tool  should  be  large 
enough  to  allow  the  stock  to  slip  through  it  nearly 
up  to  the  upset  portion. 

Welded-head  Bolts. — A  welded-head  bolt  is  made 
by  welding  a  ring  of  square  iron  around  the  shank 
to  form  the  head,  which  is  then  shaped  in  a  heading- 
tool  the  same  as  an  upset  head.  A  piece  of  square 


8o 


FORGE-PRACTICE. 


iron  of  the  proper  size  is  bent  into  a  ring,  but  not 
welded.  About  the  easiest  way  to  do  this  is  to  take 
a  bar  several  feet  long,  bend  the  ring  on  the  end,  and 
then  cut  it  off  as  shown  in  Fig.  107. 


FIG.  107. 

This  ring  is  just  large  enough,  when  the  ends  are 
slightly  separated,  to  slip  easily  over  the  shank. 

The  shank  is  heated  to  about  a  welding  heat,  the 
ring  being  slightly  cooler,  and  the  two  put  together 
as  shown  in  Fig.  107,  B.  The  head  is  heated  and 
welded,  and  then  shaped  as  described  above. 

When  welding  on  the  head  it  should  be  hammered 
square  the  first  thing,  and  not  pounded  round  and 
round.  It  is  much  easier  to  make  a  sound  weld  by 
forging  square. 

Care  must  be  used  when  taking  the  welding  heat 
to  heat  slowly,  otherwise  the  outside  of  the  ring  will 
be  burned  before  the  shank  is  hot  enough  to  stick. 

It  is  sometimes  necessary  when  heating  the  bolt- 
head  for  welding  to  cool  the  outside  ring  to  prevent 
its  burning  before  the  shank  has  been  heated  suffi- 
ciently to  weld ;  to  do  this  put  the  bolt  in  the  water 


SIMPLE    FORGED    WORK. 


8l 


sideways  just  far  enough  to  cool  the  outside  edge  of 
the  ring  and  leave  the  central  part,  or  shank,  hot. 

Tongs. — Tongs  are  made  in  a  great  variety  of 
ways,  several  of  which  are  given  below. 

Common  flat- jaw  tongs,  such  as  are  used  for 
holding  stock  up  to  about  J  inch  thick,  may  be 
made  as  follows:  Stock  about  }  inch  square 
should  be  used.  This  is  first  bent  like  A,  Fig. 
108.  To  form  the  eye  the  bent  stock  is  laid 


FIG.  108. 

across  the  anvil  in  the  position  shown  at  B,  and 
flattened  by  striking  with  a  sledge  the  edge  of  the 
anvil,  forming  the  shoulder  for  the  jaw.  A  set- 
hammer  may  be  used  to  do  this  by  placing  the 
piece  with  the  other  side  up,  flat  on  the  face  of  the 
anvil,  and  holding  the  set-hammer  in  such  a  way  as 
to  form  the  shoulder  with  the  edge  of  the  hammer, 
the  face  of  the  hammer  flattening  the  eye. 


82  FORGE-PRACTICE. 

The  long  handle  is  drawn  out  with  a  sledge, 
working  as  shown  at  C.  When  drawing  out  work 
this  way  the  forging  should  always  be  held  with 
the  straight  side  up,  the  corner  of  the  anvil  forming 
the  sharp  corner  up  against  the  shoulder  on  the 
piece.  If  the  piece  be  turned  the  other  side  up, 
there  is  danger  of  striking  the  projecting  shoulder 
with  the  sledge  and  knocking  the  work  out  of  shape. 

For  finishing  up  into  the  shoulder  a  set -hammer 
or  swage  should  be  used,  and  the  handles  should 
be  smoothed  off  with  a  flatter,  or  between  top  and 
bottom  swages.  The  jaw  may  be  flattened  as 
shown  at  D. 

The  inside  face  of  the  jaw  should  be  slightly 
creased  with  a  fuller,  as  this  insures  the  tongs  grip- 
ping the  work  firmly  with  the  sides  of  the  jaws,  and 
not  simply  touching  it  at  one  point  in  the  center,  as 
they  sometimes  do  if  this  crease  is  not  made. 

After  the  tongs  have  been  shaped,  and  are  fin- 
ished in  every  other  way,  the  hole  for  the  rivet 
should  be  punched.  The  rivet  should  drop  easily 
into  the  hole.  The  straight  end  of  the  rivet  should 
be  brought  to  a  high  heat,  the  two  parts  of  the 
tongs  placed  together  with  the  holes  in  line,  the 
rivet  inserted,  and  the  end  " headed  up."  Most  of 
the  heading  should  be  done  with  the  pene  end  of 
the  hammer.  After  riveting  the  tongs  will  prob- 
ably be  rather  ' '  stiff ' ' ;  opening  and  shutting  them 
several  times,  while  the  rivet  is  still  red-hot,  will 
leave  them  loose.  The  tongs  should  be  finished 
by  fitting  to  a  piece  of  stock  of  the  size  on  which 
they  are  to  be  used. 


SIMPLE    FORGED    WORK. 


Light  Tongs. — Tongs  may  be  made  from  flat  stock 
in  the  following  way :  A  cut  is  made  with  a  narrow 
fuller  at  the  right  distance  from  the  end  of  the  bar 
to  leave  enough  stock  to  form  the  jaw  between  the 
cut  and  the  end,  as  shown  at  A,  Fig.  109. 


FIG. 


109. 


This  end  is  bent  over  as  shown  at  B  and  a  second 
fuller  cut  made,  shown  at  C,  to  form  the  eye.  The 
other  end  of  the  bar  is  drawn  out  to  form  the  handle, 
as  indicated  by  the  dotted  lines.  The  jaw  is  shaped, 
the  rivet -hole  punched,  and  the  tongs  finished,  as 
at  D,  in  the  usual  way. 

Tongs  of  this  character  may  be  used  on  light 
work. 

Tongs  for  Round  Stock.  —  Tongs  for  holding 
round  stock  may  be  made  by  either  of  the  above 
methods,  the  operations 
in  making  being  the 
same,  with  the  exception 

of     shaping     the     jaws,         /f  ^^J    //    PM  A 
which    may  be  done    in 
this    way:     A  top  fuller 
and   bottom    swage    are  FIG.  no. 

used,  the    swage    being   of   the  size   to  which  it  is 
wished  to  finish  the  outside  of  the  jaws,  the  fuller 


84  FORGE-PRACTICE. 

the  size  of  the  inside.  The  jaw  is  held  on  the  swage, 
and  the  fuller  placed  on  top  and  driven  down  on 
it,  Fig.  no,  forcing  the  jaw  to  take  the  desired 
shape,  shown  at  A.  The  final  fitting  is  done  as 
usual,  after  the  jaws  are  riveted  together. 

Welded  Tongs. — Tongs  with  welded  handles  are 
made  in  exactly  the  same  way  as  those  with  solid, 
drawn-out  handles  excepting  that,  in  place  of  draw- 
ing out  the  entire  length  of  the  handle,  a  short  stub 
only  is  forged,  a  few  inches  long,  and  to  this  is 
welded  a  bar  of  round  stock  to  form  the  handle. 
Fig.  in  shows  one  ready  for  welding. 


FIG.  in. 

Pick-up  Tongs.  —  No  particular  description  is 
necessary  for  making  pick-up  tongs.  The  tongs 
may  be  drawn  out  of  a  flat  piece  and  bent  as 
shown  in  Fig.  112. 


FIG.  112. 


Bolt-tongs.  —  Bolt-tongs  are  easily  made  from 
round  stock,  although  square  may  be  used  to 
advantage. 

The  first  operation  is  to  bend  the  bar  in  the  shape 


SIMPLE  FORGED  WORK. 


85 


shown  in  Fig.  113.  This  may  be  done  with  a  fuller 
over  the  edge  of  the  anvil,  as  shown  at  A.  When 
bending  the  extreme  end  of  the  jaw  the  bar  should 
be  held  almost  level  at  first,  and  gradually  swung 
down,  as  shown  by  the  arrow,  until  the  end  is  prop- 
erly bent. 


FIG.  113. 


FIG.  114. 


The  eye  may  be  flattened  with  the  set-hammer, 
and  the  part  between  the  jaw  proper  and  the  eye 
worked  down  to  shape  over  the  horn  and  on  the 
anvil  with  the  same  tool. 

The  jaw  proper  is  rounded  and  finished  with  a 
fuller  and  swage,  as  shown  in  Fig.  114. 

There  is  generally  a  tendency  for  the  spring  of 
the  jaw  to  open  up  too  much  in  forging.  This 
may  be  bent  back  into  shape  either  on  the  face  of 
the  anvil,  as  shown  at  A  (Fig.  115),  or  over  the 
horn,  as  at  B. 

Another  method  of  making  the  first  bend,  when 
starting  the  tongs,  is  shown  in  Fig.  116.  A  swage- 
block  and  fuller  are  here  used;  a  swage  of  the 


86 


FORGE-PRACTICE. 


proper  size  could  of  course  be  used  in  place  of  the 
block. 


FIG.  115. 


FIG.  116. 


Ladle. — A  ladle,  similar  to  Fig.  117,  may  be 
made  of  two  pieces  welded  together,  one  piece 
forming  the  handle,  the  other  the  bowl. 

A  square  piece  of  stock  of  the  proper  thickness 
is  cut  and  "laid  out"  (or  marked  out)  like  Fig. 
118;  the  center  of  the  piece  being  first  found  by 
drawing  the  diagonals. 


\ 


FIG.  117. 


FIG.  118. 


A  circle  is  drawn  as  large  as  possible,  with  its 
center  on  the  intersection  of  the  diagonals;  the 
piece  is  cut  out  with  a  cold  chisel  to  the  circle, 
excepting  at  the  points  where  projections  are  left 
for  lips  and  for  a  place  to  weld  on  the  handle.  This 
latter  projection  is  scarfed  and  welded  to  the  strip 
forming  the  handle. 


SIMPLE  FORGED  WORK.  87 

The  bowl  is  formed  from  the  circular  part  by 
heating  it  carefully  to  an  even  yellow  heat  and 
placing  it  over  a  round  hole  in  a  swage-block  or 
other  object.  The  pene  end  of  the  hammer  is  used, 
and  the  pounding  done  over  the  hole  in  the  swage- 
block.  As  the  metal  in  the  center  is  forced  down- 
ward by  the  blow  of  the  hammer,  the  swage-block 
prevents  the  material  at  the  sides  from  following 
and  is  gradually  worked  into  a  bowl  shape. 

Fig.  119  shows  the  position  of  the  block  and  the 
piece  when  forging. 

The  bowl  being  shaped  properly,  the  lips  should 
be  formed,  and  the  top  of  the  bowl  ground  off  true. 


00Q 


FIG.  119.  FIG.  120. 

The  lips  may  be  formed  by  holding  the  part 
where  the  lips  are  to  be  against  one  of  the  smaller 
grooves  in  the  side  of  the  swage-block,  and  driving 
it  into  the  groove  by  placing  a  small  piece  of  round 
iron  on  the  inside  of  the  bowl  as  shown  in  Fig.  120. 

For  a  ladle  with  a  bowl  3%"  in  diameter,  the  diam- 
eter of  the  circle,  cut  from  the  flat  stock,  should  be 
about  4",  as  the  edges  of  the  piece  draw  in  some- 
what. Stock  for  other  sizes  should  be  in  about 
the  same  proportion.  Stock  should  be  about  J" 
thick. 


88 


FORGE-PRACTICE. 


FlG.  121. 


Machine-steel  should  be  used  for  making  the 
bowl.  If  ordinary  wrought  iron  is  used,  the  metal 
is  liable  to  split. 

Bowls. — Bowls,  and  objects  of  similar  shape, 
may  be  made  in  the  manner  described  above,  but 
care  must  be  used  not  to  do  too  much  hammering  in 
the  center  of  the  stock,  as  that  is  the  part  most 
liable  to  be  worked  too  thin. 

Chain-stop. — The  chain-stop,  shown  in  Fig.  121, 
will  serve  as  an  example  of  a  very  numerous  class 

of  forgings ;  that  is,  forg- 
'f-~ 46--M  jngs  having  a  compara- 

tively    large     projection 
on  one  side. 

Care  should  be  taken 
to  select  stock,  for  pieces 
of  this  sort,  that  will  work  into  the  proper  shape  with 
the  least  effort.  The  stock  should  be  as  thick  as 
the  thickest  part  of  the  forging, 
and  as  wide  as  the  widest  part. 
Stock,  in  this  particular  case, 

should  be  i"Xi*". 

The  different  steps  in  making 
the  forging  are  shown  in  Fig. 
122.  First  two  cuts  are  made 
i  J"  apart,  as  shown  at  A ;  then 
these  cuts  are  widened  out  with 
a  fuller,  B.  The  ends  are  then 
forged  out  square,  as  at  C.  To 
finish  the  piece  the  hole  is 
punched  and  rounded  and  the 
round. 


FIG.  122. 
ends     finished 


SIMPLE   FORGED    WORK. 


89 


is    used   it    should 
as    shown    in 


When    the    fuller 
slightly    slanting, 
Fig.  123. 

This  forces  the  metal  toward 
the  central  part  and  leaves  a 
more  nearly  square  shoulder,  in 
place  of  the  slanting  shoulder 


held 


FIG.  123. 


that  would  be  left  were  the  fuller  to  be  held  exactly 
upright. 


CHAPTER  VI. 

CALCULATION   OF   STOCK;    AND  MAKING  OP 
GENERAL  FORCINGS. 

Stock  Calculations  for  Forged  Work.— When  cal- 
culating the  amount  of  stock  required  to  make  a 
forging,  when  the  stock  has  its  original  shape 
altered,  there  is  one  simple  rule  to  follow:  Calcu- 
late the  volume  of  the  forging,  add  an  allowance 
for  stock  lost  in  forging,  and  cut  a  length  of  stock 
having  the  total  volume.  In  other  words,  the 
forging  contains  the  same  amount,  or  volume,  of 
metal,  no  matter  in  what  shape  it  may  be,  as  the 
original  stock;  an  allowance  of  course  being  made 


FIG.  124. 


for  the  slight  loss  by  scaling,  and  for  the  parts  cut 
off  in  making. 

Take  as  an  example  the  forging  shown  in  Fig. 
124,  to  determine  the  amount  of  stock  required  to 

9o 


CALCULATION    OF   STOCK;    GENERAL    FORCINGS.  91 

make  the  piece.  This  forging  could  be  made  in 
much  the  same  way  as  the  chain-stop.  A  piece  of 
straight  stock  would  be  used  and  'two  cuts  made 
and  widened  with  a  fuller,  in  the  manner  shown 
in  Fig.  125.  The  ends  on  either  side  of  the  cuts 


FIG.  125. 

are  then  drawn  down,  to  size,  as  shown  by  the 
dotted  lines,  the  center  being  left  the  size  of  the 
original  bar.  The  stock  should  be  J"  X  i",  as  these 
are  the  dimensions  of  the  largest  parts  of  the  forg- 
ing. For  convenience  in  calculating  the  forging 
may  be  divided  into  three  parts:  the  round  end 
A,  the  central  rectangular  block  B,  and  the  square 
end  C. 

The  block  B  will  of  course  require  just  2"  of 
stock. 

The  end  C  has  a  volume  of  i"Xi"X3"=f  of  a 
cubic  inch. 

The  stock  (£"Xi")  has  a  volume  of  J"Xi" 
X  i"  =  i  of  a  cubic  inch  for  each  inch  of  length. 

To  find  the  number  of  inches  of  stock  required  to 
make  the  end  C,  the  volume  of  this  end  (f  cubic 
inch)  should  be  divided  by  the  volume  of  one  inch 
of  stock  (or  i  cubic  inch).  Thus,  f  -f-  J  =  ij"- 

It  will  therefore  require  i£"  of  stock  to  make 
the  end  C\  with  allowance  for  scaling,  if". 

The  end  A  is  really  a  round  shaft,  or  cylinder, 
4"  long  and  \"  in  diameter.  To  find  the  volume 


Q2  FORGE-PRACTICE. 

of  a  cylinder,  multiply  the  square  of  half  the  diame- 
ter by  3Y7,  and  then  multiply  this  result  by  the 
length  of  the  cylinder. 

The  volume  of  A  would  be  V4  X  J/4  X  3 1/7  X  4  =  n/14. 
And  the  amount  of  stock  required  to  make  A  would 
be  n/I4-H  1/2  =  i4/7'/  in  length,  which  is  practically 
equal  to  i5/8.  To  the  above  amount  of  stock  must 
be  added  a  small  amount  for  scaling,  allowing  alto- 
gether about  1 3/4". 

The  stock  needed  for  the  different  parts  of  the 
forging  is  as  follows : 

Round  shaft  A if" 

Block  B 2" 

Square  shaft  C if" 

Total Sf" 

First  taking  a  piece  of  stock  i"Xi"X5f",  the 
cuts  would  be  made  for  drawing  out  the  ends  as 
shown  in  Fig.  125. 

In  such  a  case  as  the  above  it  is  not  always  neces- 
sary to  know  the  exact  amount  of  stock  to  cut. 
What  is  known  to  be  more  than  enough  stock  to 
make  the  forging  could  be  taken,  the  central  block 
made  the  proper  dimensions,  the  extra  metal 
worked  down  into  the  ends,  and  then  trimmed  off 
to  the  proper  length.  There  are  frequently  times, 
however,  when  the  amount  of  material  required 
must  be  calculated  accurately. 

Take  a  case  like  the  forging  shown  in  Fig.  126. 
Here  is  what  amounts  to  two  blocks,  each  2"X4" 
X6",  connected  by  a  round  shaft,  2"  in  diameter. 


CALCULATION   OF   STOCK;    GENERAL    FORCINGS. 


93 


To  make  this,  stock  2"  thick  and  4"  wide  should 
be  used,  starting  by  making  cuts  as  shown  in  Fig. 


-34- 


FIG.  126. 


127,   and  drawing  down  the  center  to   2"  round. 
It  is  of  course  necessary  to  know  how  far  apart  to 


/           A  y       ~~^     /v 

\ 

p\ 

^1 

h  —  e"  —  >f  ^A  1  —  6=  —  ^ 

FIG.  127. 

make  the  cuts  when  starting  to  draw  down  the 
center. 

The  volume  of  a  cylinder  2"  in  diameter  and 
24"  long  would  be  i"  X  i"  X  3  Y/'  X  24"  =  75  3/7  cubic 
inches,  which  maybe  taken  as  7  5 1/2  cubic  inches. 
For  each  inch  in  length  the  stock  would  have  a 
volume  of  4"X2"X  i"  =8  cubic  inches.  There- 
fore it  would  require  75  Y2~^8  =97/ie  inches  of  stock 
to  form  the  central  piece;  consequently  the  dis- 
tance between  cuts,  shown  at  A  in  Fig.  127,  would 
have  to  be  97/16".  Each  end  would  require  6"  of 
stock,  so  the  total  stock  necessary  would  be 

6"  +  6"  +  9Y16"  =  2IY1e". 

Any  forging  can  generally  be  separated  into  sev- 
eral simple  parts  of  uniform  shape,  as  was  done 
above,  and  in  this  form  the  calculation  can  be 


94  FORGE-PRACTICE. 

easily  made,  if  it  is  always  remembered  that  the 
amount  of  metal  remains  the  same,  and  in  forging, 
merely  the  shape,  and  not  the  volume,  is  altered. 

Weight  of  Forgings.— To  find  the  weight  of  any 
forging,  the  volume  may  first  be  found  in  cubic 
inches,  and  this  volume  multiplied  by  .2779,  the 
weight  of  wrought  iron  per  cubic  inch.  (If  the 
forging  is  made  of  steel,  multiply  by  .2836  in  place 
of  .2779.)  This  will  give  the  weight  in  pounds. 

Below  is  given  the  weight  of  both  wrought  and 
cast  iron  and  steel,  both  in  pounds  per  cubic  inch 
and  per  cubic  foot. 

Lbs.  per  Lbs.  per 

Cu.  Ft.  Cu.  In. 

Cast  iron  weighs 450  .2604 

Wrought  iron  weighs.  .   480  -2779 

Steel  weighs 490  -2936 

Suppose  it  is  required  to  find  the  weight  of  the 
forging  shown  in  Fig.  124.  We  had  a  volume  in 
A  of  n/14  cubic  inch,  in  C  of  V4  cubic  inch,  and  in 
B  of  i  cubic  inch,  making  a  total  of  2 15/28  cubic 
inches.  If  the  forging  were  made  of  wrought  iron, 
it  would  weight  215/28X-2779  =  -7  °f  a  pound. 

The  forging  shown  in  Fig.  126  has  a  volume  in 
each  end  of  48  cubic  inches,  and  in  the  center  of 
75f-  cubic  inches,  making  a  total  of  171^  cubic 
inches,  and  would  weigh,  if  made  of  wrought  iron, 
47.64  pounds. 

A  much  quicker  way  to  calculate  weights  is  to 
use  a  table  such  as  is  given  on  page  250.  As  steel 
is  now  commonly  used  for  making  forgings,  this 


CALCULATION    OF    STOCK;    GENERAL    FORCINGS  95 

table  is  figured  for  steel.  The  weight  given  in  the 
table  is  for  a  bar  of  steel  of  the  dimensions  named 
and  one  foot  long.  Thus  a  bar  i"  square  weighs 
3.402  Ibs.  per  foot,  a  bar  3i"Xi"  weighs  11.9  Ibs. 
per  foot,  etc. 

To  calculate  the  weight  of  the  forging  shown  in 
Fig.  126,  proceed  as  follows:  Each  end  is  2"X4" 
and  6"  long,  so,  as  far  as  weight  is  concerned,  equal 
to  a  bar  4"X2"  and  12"  long.  From  the  table, 
a  bar  4"Xi"  weighs  13.6  Ibs.  for  each  foot  in 
length;  so  a  bar  4"X2",  being  twice  as  thick, 
would  weigh  twice  as  much,  or  27.2  Ibs.,  and  as 
the  combined  length  of  the  two  ends  of  the  forging 
is  one  foot,  this  would  be  their  weight.  The  table 
shows  that  a  bar  2"  in  diameter  weighs  10.69  Ibs. 
for  every  foot  in  length;  consequently  the  central 
part  of  the  forging,  being  2  ft.  long,  would  weigh 
10.69X2,  or  21.38  Ibs.  The  total  weight  of  the 
entire  forging  would  be  48.58  Ibs.  (This  seems  to 
show  a  difference  between  this  weight  and  the 
weight  as  calculated  before,  but  it  must  be  remem- 
bered that  before  the  weight  was  calculated  for 
wrought  iron,  while  this  calculation  was  made  for 
steel.) 

Finish. — Some  forgings  are  machined,  or  "  fin- 
ished," after  leaving  the  forge-shop.  As  the  draw- 
ings are  always  made  to  represent  the  finished 
work,  and  give  the  finished  dimensions,  it  is  neces- 
sary to  make  an  allowance  for  this  finishing  when 
making  the  forging,  and  all  parts  which  have  to 
be  ''finished,"  or  "machined,"  must  be  left  with 
extra  metal  to  be  removed  in  finishing. 


9.6 


FORGE-PRACTICE. 


The  parts  required  to  be  finished  are  generally 
marked  on  the  drawing;  sometimes  the  finished 
surfaces  have  the  word  FINISH  marked  on  them; 
sometimes  the  finishing  is  shown  simply  by  the 
symbol  /,  as  used  in  Fig.  128,  showing  that  the 
shafts  and  pin  only  of  the  crank  are  to  be  finished. 


k                           ft"                         > 

r 

i"     •>! 

u*i 

1.            '  .        . 

n  —  T—  =L 

FIG.  128. 

When  all  surfaces  of  a  piece  are  to  be  finished 
the  words  FINISH-ALL-OVER  are  sometimes  marked 
on  the  drawing. 

The  allowance  for  finish  on  small  forgings  is  gen- 
erally about  Yi6"  on  each  surface ;  thus  if  a  block 
were  wanted  to  finish  4"X2"Xi",  and  Yio"  were 
allowed  for  finishing,  the  dimensions  of  the  forging 

shouldbe4l"X2j"XiJ". 

On  a  forging  like  Fig.  126,  about  \"  allowance 
should  be  made  for  finish,  if  it  were  called  for; 
thus  the  diameter  of  the  central  shaft  would  be 
2\" ,  the  thickness  of  the  ends  2\" ,  etc.  On  larger 
work  \"  is  sometimes  allowed  for  machining. 

The  amount  of  finish  allowed  depends  to  a  large 
extent  on  the  way  the  forging  is  to  be  finished.  If 
it  is  necessary  to  finish  by  filing  the  forging  should 
be  made  as  nearly  to  size  as  possible,  and  having 
a  very  slight  amount  for  finish,  Y32",  or  even  YM"f 
being  enough  in  some  cases. 


CALCULATION   OF   STOCK)     GENERAL   FORCINGS.  97 

It  is  of  course  necessary  to  take  this  into  account 
when  calculating  stock,  and  the  calculation  made 
for  the  forging  with  the  allowance  for  finish  added 
to  the  drawing  dimensions  and  not  simply  for  the 
finished  piece. 

Crank -shafts.  --  There  are  several  methods  of 
forging  crank-shafts,  but  only  the  common  com- 
mercial method  will  be  given  here. 

When  forgings  were  mostly  made  of  wrought  iron, 
cranks  were  welded  up  of  several  pieces.  One 
piece  was  used  for  each  of  the  end  shafts,  one  piece 
for  each  cheek,  or  side,  and  another  piece  for  the 
crank-pin.  Mild-steel  cranks  are  now  more  uni- 
versally used  and  forged  from  one  solid  piece  of 
stock.  The  drawing  for  such  a  crank  is  given  in 
Fig.  128;  finish  to  be  allowed  only  as  shown,  that 
is,  only  on  crank-pin  and  shafts.  The  forgings,  as 
made,  will  appear  like  the  outlines  in  Fig.  129. 
The  metal  in  the  throat  of  the  crank  is  generally 
removed  by  drilling  a  line  of  holes  and  then  sawing 
slots  where  the  sides  of  'the  crank  cheeks  should 
come,  as  shown  by  the  dotted  lines  in  Fig.  129. 


.  ..,  I 

i 

p**""! 

uJ 

,.^B  „ 

I*                             f\ 

\ 

1 

FIG.  129. 

The  central  block  is  then  easily  knocked  out.  This 
drilling  and  sawing  are  done  in  the  machine-shop. 
This  throat  can  be  formed  by  chopping  out  the 


9  8  FORGE-PRACTICE. 

surplus  metal  with  a  hot  chisel,  but  on  small  cranks, 
such  as  here  shown,  it  is  generally  cheaper  in  a  well- 
equipped  shop  to  use  the  first  method. 

The  first  step  is  to  calculate  the  amount  of  stock 
required.  Stock  iJ"X4"  should  be  used.  The 
ends,  A  and  B,  should  be  left  i}"  in  diameter  to 
allow  for  finishing.  The  end  A  contains  10.13 
cubic  inches.  Each  inch  of  stock  contains  6  cubic 
inches.  It  would  therefore  require  1.7"  of  stock 
to  form  this  end  provided  there  were  no  waste  from 
scale  in  heating.  This  waste  does  take  place,  and 
must  be  allowed  for,  so  it  will  be  safe  to  take  about 
2"  of  stock  for  this  end.  B  contains  5.22  cubic 
inches,  and  would  require  .87"  of  stock  without 
allowance  for  scale.  About  ij"  should  be  taken. 
The  stock  should  then  be  7^"  long.  The  first  step 
is  to  make  cuts  ij"  from  one  end  and  2"  from  the 
other,  and  widen  out  these  cuts  with  a  fuller,  as 
shown  in  Fig.  130. 


FIG.  130.  FIG.  131. 

These  ends  are  then  forged  out  round  in  the  man- 
ner illustrated  in  Fig.  131.  The  forging  should  be 
placed  over  the  corner  of  the  anvil  in  the  position 
shown,  the  blows  striking  upon  the  corner  of  the 
piece  as  indicated.  As  the  end  gradually  straightens 


CALCULATION    OF    STOCK;    GENERAL   FORCINGS. 


99 


out,  the  other  end  of  the  piece  is  slowly  raised  into 
the  position  shown  by  the  dotted  lines  and  the 
shaft  hammered  down  round  and  finished  up  be- 
tween swages. 

Care  must  be  taken  to  spread  the  cuts  properly 
before  drawing  down  the  ends,  otherwise  a  bad 
cold-shut  will  be  formed.  If 
the  cuts  are  left  without  spread- 
ing, the  metal  will  act  some- 
what after  the  manner  shown 
in  Fig.  132.  The  top  part  of 
the  bar,  as  it  is  worked  down, 
will  gradually  fold  over,  leav- 
ing, when  hammered  down  to 
size,  a  bad  cold-shut,  or  crack,  such  as  illustrated 
in  Fig.  132.  When  the  metal  starts  to  act  this  way, 
as  shown  by  the  upper  sketch  in  132,  the  fault  may 
be  remedied  by  trimming  off  the  corner  along  the 
dotted  line.  This  must  always  be  done  as  soon  as 
any  tendency  to  double  over  is  detected. 

Double-throw  Cranks.  —  Multiple-throw  cranks   are 


FlG- 


FIG.  133 

first   forged   flat,    rough   turned,    then   heated   and 
twisted  into  shape. 

The    double-throw    crank,    shown    in    Fig.    133, 


100 


FORGE-PRACTICE. 


would  be  first  forged  as  shown  in  Fig.  134 ;  the  parts 
shown  dotted  would  then  be  cut  out  with  the  drill 
and  saw,  as  described  above. 

After  the  pins  and  shafts  have  been  rough  turned 
— that  is,  turned  round,  but  left  as  large  as  possi- 


j 

i 
l 

1 

i       tiooerxxj      i             1 

1 

1 

i 

1 

1 

i     i 

i 

B 

A 

FIG. 

134- 

ble — the  crank  is  returned  to  the  forge-shop,  where 
it  is  heated  red-hot  and  twisted  into  the  finished 
shape. 

When  twisting,  the  crank  is  gripped  just  to  one 
side  of  the  central  bearing,  as  shown  by  the  dotted 
line  A.  This  may  be  done  with  a  vise  or  wrench, 
if  the  crank  is  small,  or  the  crank  may  be  placed 
on  the  anvil  of  a  steam-hammer  and  the  hammer 
lowered  down  on  it  to  hold  it  in  place. 

The  other  end  of  the  crank  is  gripped  on  the  line 
B  and  twisted  into  the  required  shape. 


FIG.  135. 

A  wrench  of  the  shape  shown  in  Fig.  135  is  very 
convenient   for   doing  work   of   this  character.     It 


CALCULATION   OF   STOCK;    OLNERAI,   FQ^GINGS. 


101 


may  be  formed  by  bending  a  U  out  of  flat  stock, 
bent  edgewise,  and  welding  on  a  handle. 

Three-throw     Crank. — Fig.     136     shows    what     is 
known  as  a  " three- throw"  crank.     The  forging  for 


— 



— 

N 

f      -r 

if 

•^ 

—  1  

-< 

/        t 

— 

-^7 

i  — 

P  

i                      8* 

i- 

«-44/» 

. 

-— 

<• 

*-&4r+\ 
1-7^" 

'  1>!i3 

| 

FIG.  136. 

this  is  first  made  as  shown  by  the  solid  lines  in  Fig. 
137.     The    forging    is    drilled    and    sawed    in    the 


T 

4 

1 

fri  L-5i 

2 

-if 

1 

. 

—  j-j  —  j 

*\/ 

<U 

1-R  "  

*  3^  . 

FIG.  137. 

machine-shop  to  the  dotted  lines,  and  pins  rough 
turned,  being  left  as  large  as  possible.  The  forging 
is  returned  to  the  forge-shop,  heated,  and  bent  into 
the  shape  of  the  finished  crank.  It  is  then  sent 
to  the  machine-shop  and  finished  to  size.  Four- 
throw  cranks  are  also  made  in  this  manner. 

The  slots  are  sometimes  cut  out  in  the  forge-shop 
with  a  hot  chisel,  but,  particularly  on  small  work, 
it  is  generally  more  economical  to  have  them  sawed 
out  in  the  machine-shop.  This  is  especially  so  of 
multiple-throw  cranks,  which  must  be  twisted. 


102 


FQSjGE-PRACTICE. 


Knuckles.— There  is  a  large  variety  of  forgings 
which  can  be  classed  under  one  head — such  forg- 
ings as  the  forked  end  of  a  marine  connecting-rod, 
the  knuckle-joints  sometimes  used  in  valve-rods, 
and  others  of  this  character,  such  as  illustrated  in 
Figs.  139,  140,  141,  E. 


FIG.  141. 

Connecting-rod  End. — Fig.  138  shows  the  shaped 
end  often  used  on  the  crank  end  of  connecting- 
rods.  The  method  of  forming  this  is  the  same  as 
the  first  step  in  forging  the  other  pieces  above  men- 
tioned. 

The  stock  used  for  making  this  should  be  as  wide 


CALCULATION   OF   STOCK;    GENERAL   FORCINGS.  103 


as  B  and  somewhat  more  than  twice  as  thick  as  A. 
The  first  step  is  to  make  two 
fuller  cuts  as  shown  at  A,  Fig. 

142,  using  a  top  and  bottom 
fuller    and    working    in    both 
sides  at  the  same  time.     When 
working  in  both  sides  of  a  bar 
this  way,  it  should  be  turned 
frequently,   bringing   first   one 
side,    then    the    other,    upper- 
most.    In   this   way   the   cuts 
will   be   worked   to   the   same 
depth  on  both  sides,   while  if 
the  work  is  held  in  one  posi- 
tion, one  cut  will  generally  be 
deeper  than  the  other.     After 
the  cuts   are  made,    the   left- 
hand  end  of  the  bar  is  drawn 
out  to  the  proper  size  and  the 

right-hand  end  punched  and  split  like  B.  Some- 
times when  the  length  D,  Fig.  138,  is  compara- 
tively short  and  the  stock  wide,  instead  of  being 
punched  and  split,  the  end  of  the  bar  is  cut  out,  as 
shown  at  C,  Fig.  142,  with  a  right  angle  or  curved 
cutter. 

The  split  ends  are  spread  out  into  the  position 
shown  at  D,  and  drawn  down  to  size  over  the  cor- 
ner of  the  anvil,  in  the  manner  illustrated  in  Fig. 

143.  These    ends    are    then    bent    back    into    the 
proper   position   for   the   finished   forging.     Gener- 
ally when  the  ends  are  worked  out  and  bent  back 
in  this  manner,  a  bump  is  left  like  that  indicated 


FIG.  142. 


104 


FORGE-PRACTICE. 


by  the  arrow-point  at  E,  Fig.   142.       This  should 
be  trimmed  off  along  the  dotted  line. 

Knuckle. — The    knuckle,   Fig.    139,   is   started    in 
exactly  the  same  way,  but  after  being  forged  out 


FIG.  143.  FIG.  144. 

straight,  as  above,  the  tips  of  these  ends  are  bent 
down,  forming  a  U-shaped  loop  of  approximately 
the  shape  of  the  finished  knuckle.  A  bar  of  iron 
of  the  same  dimension  at  the  inside  of  the  finished 
knuckle  is  then  inserted  between  the  sides  of  the 
loop  and  the  sides  closed  down  flat  over  it,  Fig. 
144. 

Forked-end  Connecting-rod. — Fig.  140  is  made  in 
the  same  manner.  The  shaft  5  should  be  drawn 
down  into  shape  and  rounded 
up  before  the  other  end  is 
split.  After  the  split  ends 
have  been  bent  back 
straight,  the  shoulder  A 
should  be  finished  up  with 
a  fuller  in  the  manner  shown 
in  Fig.  145.  The  rounded 
ends  B-B  should  be  formed  before  the  piece  is  bent 


FIG.  145. 


CALCULATION    OF    STOCK;    GENERAL    FORCINGS.  105 

into  shape.  The  final  bending  can  be  done  over  a 
cast-iron  block  of  the  right  shape  and  size  if  the 
forging  is  a  large  one  and  several  of  the  same  kind 
are  wanted. 

Hook  with  Forked  End. — Fig.  141,  E  is  a  forging 
which  also  conies  in  this  general  class.  This  is 
made  from  f "  square  stock.  The  end  of  the  bar  is 
first  drawn  down  to  3/16"  round.  This  round  end  is 
put  through  the  hole  of  a  heading-tool,  and  the 
square  part  is  split  with  a  hot  chisel,  the  cut  wid- 
ened out,  and  the  sides  hammered  out  straight  on 
the  tool.  The  different  steps  are  shown  in  Fig. 
141. 

Wrench,  Open-end. — Open-end  wrenches  of  the 
general  class  shown  in  Fig.  146  may  be  made  in 


FIG.  146. 

several  different  ways.  It  would  be  possible  to 
make  this  by  the  same  general  method  followed 
for  making  the  forked  end  of  the  connecting-rod 
described  above.  Ordinary  size  wrenches  are  more 
easily  made  in  the  way  illustrated  in  Fig.  147. 

A  piece  of  stock  is  used,  wide  enough  and  thick 
enough  to  form  the  head  of  the  wrench.  This  is 
worked  in  on  both  sides  with  a  fuller  and  the  head 
rounded  up  as  shown.  A  hole  is  then  punched 
through  the  head  and  the  piece  cut  out  to  form 
the  opening,  as  shown  by  the  dotted  lines  at  B. 

This  wrench  could  also  be  made  by  bending  up 


io6 


FORGE-PRACTICE. 


a  U  from    the  proper  size  flat    stock   and  welding 
on  a  handle. 


FIG.  147. 

The  solid-forged  wrench  is  the  more  satisfactory. 
Socket- wrench.  —  The     socket- wrench,   shown   in 
Fig.    148,   may  be  made  in  several  ways.     About 

the  easiest,  on  "hurry- 
up"  work,  is  the  method 
shown  in  Fig.  149.  Here 
a  stub  is  shaped  up  the 
same  size  and  shape  as 
the  finished  hole  is  to  be.  A  ring  is  bent  up  of  thin 
flat  iron  and  this  ring  welded  around  the  stub. 


FIG.  148. 


FIG.  149. 

The  width  of  the  ring  should  of  course  be  equal  to 
the  length  of  the  hole  plus  the  lap  of  the  weld. 

When   finishing    the   socket,  a   nut  or  bolt-head 
the  size  the  wrench   is   intended  to  fit  should  be 


CALCULATION  OF   STOCK;    GENERAL   FORCINGS.  1 07 

placed  in   the    hole  and  the   socket  finished  over 
this  between  swages. 

A  better  way  of  making  wrenches  of  this  sort  is 
to  make  a  forging  having 
the  same  dimensions  as 
the  finished  wrench,  but 
with  the  socket  end 
forged  solid.  The  socket 
end  should  then  be 
drilled  to  a  depth  slightly 
greater  than  the  socket  is 
wanted.  The  diameter  of 
the  drill  should  be,  as 

shown  in  Fig.  150,  equal  to  the  shortest  diameter  of 
the  hole. 

After  drilling,  the  socket  end  is  heated  red-hot 
and  a  punch  of  the  same  shape  as  the  intended  hole 
driven  into  it.  The  end  of  the  punch  should  be 
square,  with  the  corners  sharp.  As  the  punch  is 
driven  in,  the  corners  will  shave  off  some  of  the 
metal  around  the  hole  and  force  it  to  the  bottom 
of  the  hole,  thus  making  it  necessary  to  have  the 
drilled  hole  slightly  deeper  than  the  socket  hole  is 
intended  to  finish. 

While  punching,  the  wrench  may  be  held  in  a 
heading  tool,  or  if  the  wrench  be  double-ended,  in  a 
pair  of  special  tongs,  as  shown  in  Fig.  150. 

Split  Work. — There  is  a  great  variety  of  thin 
forgings,  formed  by  splitting  a  bar  and  bending 
the  split  parts  into  shape.  For  convenience,  these 
can  be  called  split  forgings. 

Fig.   151  is  a  fair  sample  of  this  kind  of  work. 


io8 


FORGE-PRACTICE. 


This  piece  could  be  made  by  taking  two  flat  strips 
and  welding  them  across  each  other,  but,  particu- 


/\  , 


FIG.  151. 


FIG.  152. 


larly  if  the  work  is  very  thin,  this  is  rather  a  diffi- 
cult weld  to  make. 

An  easier  way  is  to  take  a  flat  piece  of  stock  of 
the  proper  thickness  and  cut  it  with  a  hot  chisel, 
as  shown  by  the  solid  lines  in  Fig.  152.  The  four 
ends  formed  by  the  splits  are  then  bent  at  right 
angles  to  each  other  as  shown  by  the  dotted  lines, 
and  hammered  out  pointed  as  required. 

If  machine  steel  stock  is  used,  it  is  not  generally 
necessary  to  take  any  particular  precautions  when 


FIG.  153. 

splitting  the  bar,  but  if  the  material  used  is  wrought 
iron,  it  is  necessary  to  punch  a  small  hole  through 


CALCULATION    OF    STOCK;    GENERAL    FORCINGS. 


the  bar  where  the  end  of  the  cut  comes,  to  prevent 
the  split  from  extending  back  too  far. 

Fig.  153  shows  several  examples  of  this  kind  of 
work.  The  illustrations  show  in  each  case  the 
finished  piece,  and  also  the  method  of  cutting  the 
bar.  The  shaded  portions  of  the  bar  are  cut  away 
completely. 

Expanded  or  Weldless  Eye.  —  Another  forging  of 
the  same  nature  is  the  expanded  eye  in  Fig.  154. 


FIG.  154. 


FIG.  155. 


To  make  this,  a  flat  bar  is  forged  rounding  on  the 
end,  punched  and  split  as  shown.  The  split  is 
widened  out  by  driving  a  punch,  or  other  tapering 
tool  into  it,  and  the  forging  finished  by  working 
over  the  horn  of  the  anvil,  as  shown  in  Fig.  155. 

If  the  dimensions  of  the  eye  are  to  be  very  accu- 
rate, it  will  be  necessary  to  make  a  calculation  for 
the  length  of  the  cut.  This  can  be  done  as  follows: 
Suppose  the  forging,  for  the  sake  of  convenience  in 
calculating,  to  be  made  up  of  a  ring  3"  inside  diame- 
ter and  sides  \"  wide,  placed  on  the  end  of  a  bar 
ij"  wide.  The  first  thing  is  to  determine  the  area 
of  this  ring.  To  do  this  find  the  area  of  the  out- 


IIO  FOR  G:s -PRACTICE. 

side  circle  and  subtract  from  it  the  area  of  the 
inside  circle.  (Areas  may  be  found  in  table,  page 
243.) 

Area  of  outside  circle =  12  . 57  sq.  in. 

"     "  inside       "     =    7.07    "     " 

"     "  ring =    5.50    "    " 

The  stock,  being  ij"  wide,  has  an  area  of  ij 
sq.  in.  for  every  inch  in  length,  and  it  will  take  3!" 
of  this  stock  to  form  the  ring,  as  we  must  take  an 
amount  of  stock  having  the  same  area  as  the  ring. 
This  will  be  practically  311/I6". 

The  stock  should  be  punched  and  split,  as  shown 
in  Fig.  154.  It  will  be  noticed  that  the  punch- 
holes  are  f"  from  the  end,  while  the  stock  is  to  be 
drawn  to  \" .  The  extra  amount  is  given  to  allow 
for  the  hammering  necessary  to  form  the  eye. 

Weldless  Rings. — Weldless  rings  can  be  made  in 
the  above  way  by  splitting  a  piece  of  flat  stock  and 
expanding  it  into  a  ring,  or  they  can  be  made  as 
follows:  The  necessary  volume  of  stock  is  first 
forged  into  a  round  flat  disc  and  a  hole  is  punched 
through  the  center.  The  hole  should  be  large 
enough  to  admit  the  end  of  the  horn  of  the  anvil. 
The  forging  is  then  placed  on  the  horn  and  worked 
to  the  desired  size  in  the  manner  indicated  in 
Fig.  155.  Fig.  156  shows  the  different  steps  in 
the  process — the  disc,  the  punched  disc,  and  the 
finished  ring. 

Rings  of  this  sort  are  made  very  rapidly  under 
the  steam-hammer  by  a  slight  modification  of  this 


CALCULATION    OF    STOCK;    GENERAL    FORCINGS.  1IX 

method.     The  discs   are  shaped  and  punched  and 
then    forged    to    size   over    a    ' '  mandril. "      A    U- 


FIG.  156.  FIG.  157. 

shaped  rest  is  placed  on  the  anvil  of  the  steam- 
hammer,  the  mandril  is  slipped  through  the  hole 
in  the  disc  and  placed  on  the  rest,  as  shown  in 
Fig.  157.  The  blows  come  directly  down  upon 
the  top  side  of  the  ring,  it  being  turned  between 
each  two  blows.  The  ring  of  course  rests  only  upon 
the  mandril.  As  the  hole  increases  in  size,  larger 
and  larger  mandrils  are  used,  keeping  the  mandril 
as  nearly  as  possible  the  same  size  as  the  hole. 

Forging  a  Hub,  or  Boss. — -Fig.  158  is  an  example 
of  a  shape  very  often  met  with  in  machine  forging: 
a  lever,  or  some  flat  bar  or  shank,  with  a  "boss" 


FIG.  158.  FIG.  159. 

formed  on  one  end.  This  may  be  made  in  two 
ways — either  by  doubling  over  the  end  of  the  bar, 
as  shown  in  Fig.  159,  and  making  a  fagot-weld  of 
sufficient  thickness  to  form  the  boss,  or  by  taking  a 
bar  large  enough  to  form  the  boss  and  drawing 
down  the  shank.  The  second  method  will  be 


112 


FORGE-PRACTICE. 


described,  as  no  particular  directions  are  necessary 
for  the  weld,  and  after  welding  up  the  end,  the 
boss  is  rounded  up  in  the  same  way  in  either  case. 
The  stock  should  be  large  enough  to  form  the  boss 
without  any  upsetting. 

A  bar  of  stock  is  taken,  for  the  forging  shown 
above,  2"  wide  and  2"  thick.  The  first  step  is  to 
make  a  cut  about  2"  from  the  end,  with  a  fuller, 
like  A,  Fig.  160. 


FIG.  160. 

The  stock,  to  the  right  of  the  cut,  is  then  flat- 
tened down  and  drawn  out  to  size,  as  shown  at  B. 
In  drawing  out  the  stock,  certain  precautions  must 
be  taken  or  a  "cold-shut"  will  be  formed  close  to 
the  boss.  If  the  metal  is  allowed  to  flatten  down 
into  shape  like  Fig.  C,  the  corner  at  X  will  over- 
lap, and  work  into  the  metal,  making  a  crack  in 
the  work  which  will  look  like  Fig.  E.  This 


CALCULATION    OF    STOCK;    GENERAL    FORCINGS.  113 

is  quite  a  common  fault,  and  whenever  a  crack 
appears  in  a  forging  close  to  a  shoulder,  it  is  gener- 
ally caused  by  something  of  this  sort — that  is,  by 
some  corner  or  part  of  the  metal  lapping  over  and 
cutting  into  the  forging.  When  one  of  these  cracks 
appears,  the  only  way  to  remedy  the  evil  is  to  cut 
it  out  as  shown  by  the  dotted  lines  in  E.  For  this 
purpose  a  hot-chisel  is  sometimes  used,  with  a 
blade  formed  like  a  gouge. 

Fig.  D  shows  the  proper  way  to  draw  out  the 
stock;  the  corner  in  question  should  be  forged 
away  from  the  boss  in  such  a  manner  as  to  grad- 
ually widen  the  cut.  The  bar  should  now  be 
rounded  up  by  placing  the  work  over  the  corner  of 
the  anvil,  as  shown  in  Fig.  161.  First  forge  off  the 


FIG.  161. 

corners  and  then  round  up  the  boss  in  this  way. 
To  finish  around  the  corner  formed  between  the 
boss  and  the  flat  shank,  a  set-hammer  should  be 
used.  Sometimes  the  shank  is  bent  away  from 
the  boss  to  give  room  to  work,  and  a  set -hammer, 
or  swage,  used  for  rounding  the  boss  as  shown. 


FORGE-PRACTICE. 


After  the  boss  is  finished,  the  shank  is  straightened. 
The  boss  should  be  smoothed  up  with  a  swage. 

Ladle   Shank. — The   ladle    shank,   shown    in   Fig. 
162,  may  be  made  in  several  ways.     It  is  possible 

to  make  it  solid  without 
any  welds,  or  the  handle 
may  be  welded  on  a  flat 
bar  and  the  bar  bent  into 
a  ring  and  welded,  or  the 
ring  and  handle  may  be 
forged  in  one  piece  and 
the  ring  closed  together  by  welding.  The  last- 
mentioned  method  is  as  follows :  The  stock  should 
be  about  i"  square.  It  is  necessary  to  make  a 


FIG.  162. 


FIG.  163. 

rough  calculation  of  the  amount  of  this  size  stock 
required  to  form  the  ring  of  the  shank. 


If  the  rin£ 


CALCULATION    OF    STOCK;    GENERAL    FORCINGS.  115 

were  made  of  f'Xi"  stock,  about  23^"  would  be 
required;  now  as  i"Xi"  stock  is  the  same  width 
and  about  two  and  one-half  times  as  thick  as 
J"Xi"  stock,  every  inch  of  the  i"Xi"  will  make 
about  2j"  of  f'Xi",  consequently  about  9^"  of 
the  i"  square  will  be  required  to  form  the  ring. 

A  fuller  cut  is  made  around  the  bar,  as  shown 
at  A,  Fig.  163.  This  should  be  made  about  9^" 
from  the  end  of  the  bar.  The  left-hand  end  of  the 
bar  is  drawn  down  to  J"  in  diameter  to  form  the 
handle.  If  the  work  is  being  done  under  a  steam 
or  power  hammer,  enough  stock  may  be  drawn 
out  to  form  the  entire  handle,  but  if  working  on 
the  anvil,  it  will  probably  be  more  satisfactory  to 
draw  out  only  enough  stock  to  make  a  ' '  stub  "4"  °r 
5"  long.  To  this  stub  may  be  welded  a  round  bar 
to  form  the  handle. 

After  drawing  out  the  handle,  the  g$"  square 
end  of  the  stock  is  split,  as  shown  by  the  dotted 
lines  at  B.  These  split  ends 
are  spread  apart,  as  shown 
at  C,  forged  into  shape,  and 
bent  back  to  the  position 
shown  by  the  dotted  lines. 

The  ring  is  completed  by  FlG*  l64> 

cutting  the  ends  to  the  proper  length,  scarfing, 
bending  into  shape,  and  welding,  as  indicated  in 
Fig.  164. 

If  for  any  reason  it  is  necessary  to  make  a  forg- 
ing of  this  kind  without  a  weld  in  the  ring,  it  may 
be  done  by  the  method  shown  in  Fig.  165.  The 
split  in  this  case  should  not  extend  to  the  end  of  the 


n6 


FORGE-PRACTICE. 


bar.     About  f "  or  £"  of  stock  should  be  left  uncut 
at  the  end.       This   split  is  widened  out  and  the 


FIG.  165. 

sides  drawn  down  and  shaped  into  a  ring  as  desired. 
Starting-lever. ^The  lever  shown  in  Fig.  166  is  a 


FIG.  166 

shape  sometimes  used  for   levers  used  to   turn  the 

fly-wheels   of    engines   or  other    heavy  wheels    by 

gripping  the  rim. 

The  method  used  in  making  the  lever  is  shown 

in  Fig.   167.      The  end  is  first  drawn  down  round 

and  the  handle  formed. 
The  other  end  is  then 
split,  forged  down  to 
size,  and  bent  at  right 
angles  to  the  handle. 
After  trimming  to  the 
proper  length,  the  flat 
ends  are  bent  into  shape. 
If  this  shaped  end  is 

very  heavy,  it  may  be  necessary  to  forge  it  hr  the 


B    j-. 
—  ' 


CALCULATION   OF    STOCK;    GENERAL    FORCINGS. 


117 


shape  of  a  solid  block,  as  shown  in  Fig.   168,  and 
then    either    work    in    the    depression 
shown   by    the    dotted   lines,    with   a 
fuller  and  set-hammers,  or  the  dotted 
line  may  be  cut  out  with  a  hot-chisel. 

Moulder's    Trowel. — The    moulder's  trowel  shown 
in  Fig.  169  gives  an  example  of  the  method  used  in 


FIG.  168. 


FIG.  169. 

making  forgings  of  a  large  class,  forgings  having  a 
wide  thin  face  with  a  stem,  comparatively  small, 
forged  at  one  end. 

The  stock  to  be  used  for  the  trowel  shown  should 
be  about  J"Xi".  This  is  thick  enough  to  allow 
for  the  formation  of  the  ridge  at  R. 


FIG.  170. 

Fig.  170  shows  the  general  method  employed. 
The  forging  is  started  by  making  nicks  like  A,  with 
the  top  and  bottom  fuller.  One  end  is  drawn  down 
to  form  the  tang  for  the  handle.  This  should  not 


1 1 8  FORGE-PRACTICE. 

be  forged  down  pointed,  as  required  when  com- 
pleted, but  the  entire  length  of  handle  should  be 
forged  square  and  about  the  size  the  largest  part  is 
required  to  finish  to.  The  handle  is  then  bent  up 
at  right  angles,  as  at  B,  and  the  corner  forged 
square  in  the  same  manner  that  the  corner  of  a 
bracket  is  shaped  up  sharp  and  square  on  the  out- 
side. 

After  this  corner  is  formed,  the  blade  is  drawn 
down  to  size  on  the  face  of  the  anvil. 

When  flattening  out  the  blade,  in  order  to  leave 
the  ridge  shown  at  R,  Fig.  169,  the  work  should 
be  held  as  shown  at  C,  Fig.  170.  Here  the  handle 
is  held  pointing  down  and  against  the  side  of  the 
anvil.  By  striking  directly  down  on  the  work,  and 
covering  the  part  directly  over  the  edge  of  the  anvil 
with  the  blows,  all  of  the  metal  on  the  anvil  will  be 
flattened  down,  leaving  the  metal  not  resting  on 
the  anvil  unworked.  By  swinging  the  piece  around 
into  a  reverse  position  the  other  edge  of  the  blade 
may  be  thinned  down.  If  care  be  taken  to  hold 
the  trowel  in  the  proper  position  while  thinning 
out  the  blade,  a  small  triangular-shaped  piece  next 
the  handle  will  be  left  thicker  than  the  rest  of  the 
blade.  This  raised  part  will  form  the  ridge  shown 
at  R,  Fig.  169. 

The  same  result  may  be  obtained  by  placing  the 
trowel,  other  side  up,  on  the  face  of  the  anvil  and 
using  a  set-hammer,  or  flatter,  to  thin  out  the  blade. 

Welded  Brace. — Fig.  171  shows  a  form  of  brace, 
or  bracket,  sometimes  used  for  holding  swinging 
signs  and  for  various  other  purposes. 


CALCULATION    OF    STOCK;    GENERAL    FORCINGS.  II(j 

The  bracket  in  this  case  is  made  of  round  stock; 
but  the  same  method  may  be  followed  in  making 
one  of  flat  or  square  material. 


FiG.   171. 

The  stock  is  first  scarfed  on  one  end  and  this  end 
doubled  over,  forming  a  loop,  as  shown  in  Fig.  172. 


-CUT 


FIG.  172. 

The  loop  is  welded  and  then  split,  the  ends  straight- 
ened out  and  flattened  into  the  desired  shape  as 
illustrated. 


FIG.   173. 

Welded  Fork.— The  welded  fork,  shown  in  Fig. 
173,  is  made  in  the  same  way  as  the  brace  de- 
scribed above. 


CHAPTER  VII. 


STEAM-HAMMER  WORK. 

General  Description  of  Steam-hammer. — The  gen- 
eral shape  of  small  and  medium  steam-hammers 

is  shown  in  Fig.  174. 
This  type  is  known  as 
a  single  -  frame  ham- 
mer. 

The  size  of  a  steam- 
hammer  is  determined 
by  the  weight  of  its 
falling  parts ;  thus  the 
term  a  400 -Ib.  ham- 
mer would  mean  that 
the  total  weight  of 
the  ram,  hammer-die, 
and  piston-rod  was  400 
Ibs. 

Steam-hammers  are 
made  in  this  general 
style  from  200  Ibs.  up. 

The  anvil  is  entire- 
ly separate  from  the 


FIG.  174. 
separate  foundation. 


frame  of  the  hammer, 
and   each   rests   on   a 


120 


STEAM-HAMMER   WORK.  121 

The  foundation  for  the  frame  generally  takes  the 
shape  of  two  blocks  of  timber  or  masonry  capped 
with  timber — one  in  front  and  one  behind  the  anvil 
block.  The  anvil  foundation  is  placed  between 
the  two  blocks  of  the  frame  foundation,  and  is 
larger  and  heavier. 

The  object  of  separating  the  anvil  and  frame  is  to 
allow  the  anvil  to  give  under  a  heavy  blow  with- 
out disturbing  the  frame  or  its  foundation. 

Hammer-dies. — The  dies  most  commonly  used  on 
steam-hammers  have  flat  faces ;  the  upper  or  ham- 
mer die  being  the  same  width,  but  sometimes 
shorter  in  length  than  the  lower  or  anvil  die. 

Tool-steel  makes  the  best  dies,  but  chilled  iron 
is  also  used  to  a  very  large  extent.  Sometimes, 
for  forming  work,  even  gray  iron  castings  are  used. 
Flat  dies  made  of  tool-steel  are  sometimes  used 
without  hardening.  Dies  made  this  way,  when 
worn,  may  be  faced  off  and  used  again  without 
the  bother  of  annealing  and  rehardening. 

For  special  work  the  dies  are  made  in  various 
shapes,  the  faces  being  more  or  less  in  the  shape  of 
the  work  to  be  formed.  When  the  die-faces  are 
shaped  to  the  exact  form  of  the  finished  piece,  the 
work  is  known  as  drop-forging. 

Tongs  for  Steam-hammer  Work. — The  tongs  used 
for  holding  work  under  the  steam-hammer  should 
be  very  carefully  fitted  and  the  jaws  so  shaped 
that  they  hold  the  stock  on  all  sides.  Ordinary 
flat- jawed  tongs  should  not  be  used,  as  the  work 
is  liable  to  be  jarred  or  slip  out  sideways. 

Fig.  175  shows  the  jaws  of  a  pair  of  tongs  fitted 


122 


FORGE-PRACTICE. 


to    square   stock.     Tongs   for   other   shaped   stock 

should  have  the  jaws 
formed  in  a  correspond- 
ing way;  that  is,  the  in- 
side of  the  jaws,  viewed 
from  the  end,  should  have 


FIG.  175. 


the  same  shape  as  the  cross-section  of  the  stock  they 
are  intended  to  hold,  and  should  grip  the  stock 
firmly  on  at  least  three  sides. 

Flat-jawed  tongs  can  be  easily  shaped  as  above 
in  the  manner  shown  in  Fig.   176.     The  tongs  are 


FIG.  176. 

heated  and  held  as  shown,  by  placing  one  jaw, 
inside  up,  on  a  swage.  The  jaw  is  grooved  or 
bent  by  driving  down  a  top-fuller  on  it.  After 
shaping  the  other  jaw  in  the  same  way,,  the  final 
fitting  is  done  by  inserting  a  short  piece  of  stock  of 
the  proper  size  in  the  jaws  and  closing  them  down 
tightly  over  this  by  hammering. 

When  fitting  tongs  to  round  stock,  the  finishing 


STEAM-HAMMER    WORK. 


123 


may  be  done  between  swages,  the  stock  being  kept 
between  the  jaws  while  working  them  into  shape. 

Tongs  for  heavy  work  should  have  the  jaws 
shaped  as  shown  in  Fig.  177.  When  in  use,  tongs 
of  this  kind  are  held  by 
slipping  a  link  over  the 
handles  to  force  them  to- 
gether. On  very  large  sizes, 
this  link  is  driven  on  with  a 
sledge. 

To  turn  the  work  easily, 
the  link  is  sometimes  made  in  the  shape  shown  in 
Fig.  178,  with  a  handle  projecting  from  each  end. 


FIG.  177. 


FIG.  178. 

Hammer-chisels. — The  hot-chisel  used  for  cutting 
work  under  the  hammer  is  shaped,  ordinarily,  like 
Fig.  179.  This  is  sometimes  made  of  solid  tool- 


STEEL 


IRON 


FIG.  179. 


FIG.  180. 


steel,  and  sometimes  the  blade  is  made  of  tool-steel 
and  has  a  wrought-iron  handle  welded  on.  Fig. 
1 80  shows  the  method  of  welding  on  the  wrought- 
iron  handle. 


124 


FORGE-PRACTICE. 


The  handle  of  the  chisel,  close  up  to  the  blade,  is 
hammered  out  comparatively  thin.  This  is  to 
allow  the  blade  to  spring  slightly  without  snapping 
off  the  handle.  The  hammer  will  always  knock 
the  blade  into  a  certain  position,  and  as  the  chisel 
is  not  always  held  in  exactly  the  right  way,  this 
thin  part  of  the  handle  permits  a  little  ' '  give  ' ' 
without  doing  any  harm. 

The  force  of  the  blow  is  so  great  when  cutting, 
that  the  edge  of  the  chisel  must  be  left  rather 
blunt.  The  edge  should  be  square  across,  and  not 
rounding.  The  proper  shape  is  shown  at  A,  Fig. 


FIG.  181. 


181.  Sometimes  for  special  work  the  edge  may 
be  slightly  beveled,  as  at  B  or  C,  but  should  never 
be  shaped  like  D. 

Sometimes  a  bar  is  cut  or  nicked  with  a  cold- 
chisel  under  the  hammer. 
The  chisel  used  is  shaped 
like  Fig.  182,  being  very 
flat  and  stumpy  to  resist  the 
crushing  effect  of  heavy  blows.  The  three  faces 
of  the  chisel  are  of  almost  equal  width. 

Cutting  Hot  Stock. — Hot  cutting  is  done  under  the 


FIG.  182. 


STEAM-HAMMER    WORK. 


125 


steam-hammer  in  much  the  same  way  as  done  on 
the  anvil. 

If  the  chisel  be  held  perfectly  upright,  as  shown 
at  A,  Fig.  183,  the  cut  end  of  the  bar  will  be  left 


7 


FIG.  183. 

bulging  out  in  the  middle.  When  the  end  is  wanted 
square  the  cut  should  be  started  with  the  chisel 
upright,  but  once  started,  the  chisel  should  be  very 
slightly  tipped,  as  shown  at  B.  When  cutting 
work  this  way  the  cut  should  be  made  about  half 
way  through  from  all  sides.  When  cutting  off 
large  pieces  of  square  stock  the  chisel  should  be 
driven  nearly  through  the  bar,  leaving  only  a  thin, 
strip  of  metal,  J"  or  \"  thick,  joining  the  twc 
pieces,  A,  Fig.  184.  The  bar  is  then  turned  over 


FIG.  184. 

on  the  anvil  and  a  thin  bar  of  steel  laid  directly  on 
top  of  this  thin  strip,  as  shown  at  B,  Fig.  184. 
One  hard  blow  of  the  hammer  sends  the  thin  bar 
of  steel  between  the  two  pieces  and  completely 
cuts  out  the  thin  connecting  strip  of  metal.  This 


126  FORGE-PRACTICE. 

leaves  the  ends  of  both  pieces  smooth,  while  if  the 

chisel  is  used  for  cutting 
on  both  sides,  the  end  of 
one  piece  will  be  smooth 
and  the  other  will  have  a 
fin  left  on  it. 

For  cutting  up  into  corners  on  the  ends  of  slots 
bent  cutters  are  sometimes  used;  such  a  cutter  is 
shown  in  Fig.  185.  These  cutters  are  also  made 
curved,  and  special  shapes  made  for  special  work. 

General  Notes  on  Steam-hammer. — When  working 
under  the  hammer,  great  care  should  always  be 
taken  to  be  sure  that  everything  is  in  the  proper 
position  before  striking  a  blow.  The  work  must 
rest  flat  and  solid  on  the  anvil,  and  the  part  to  be 
worked  should  be  held  as  nearly  as  possible  below 
the  center  of  the  hammer-die ;  if  the  work  be  done 
under  one  edge  or  corner  of  the  hammer-die,  the 
result  is  a  ' '  foul ' '  blow,  which  has  a  tendency  to 
tip  the  ram  and  strain  the  frame. 

When  tools  are  used,  they  should  always  be  held 
in  such  a  way  that  the  part  of  the  tool  touching 
the  work  is  directly  below  the  point  of  the  tool  on 
which  the  hammer  will  strike.  Thus,  supposing  a 
piece  were  being  cut  off  under  the  hammer,  the 
chisel  should  be  held  exactly  upright,  and  directly 
under  the  center  of  the  hammer,  as  shown  at  A, 
Fig.  1 86.  In  this  way  a  fair  cut  is  made.  If  the 
chisel  were  not  held  upright,  but  slantingly,  as 
shown  at  B,  the  result  of  the  blow  would  be  as 
shown  by  the  dotted  lines,  the  chisel  would  be 
turned  over  and  knocked  flat,  and,  in  some  cases, 


STEAM-HAMMER    WORK. 


127 


might  be   even  thrown  very   forcibly  from  under 
the  hammer. 

When  a  piece  is  to  be  worked  out  to  any  great 
extent,  the  blows  should  be  heavy,  and  the  end  of 


^7 


FIG.  186. 


the  stock  being  hammered  should  bulge  out  slightly, 
like  A,  Fig.  187,  showing  that  the  metal  is  being 


FIG.  187. 

worked  clear  through.  If  light  blows  are  used  the 
end  of  the  piece  will  forge  out  convex,  like  B,  show- 
ing that  the  metal  on  the  outside  of  the  bar  has 
been  worked  more  than  that  on  the  inside.  If  this 
sort  of  work  is  continued,  the  bar  will  split  and 
work  hollow  in  the  center,  like  C. 

Round  shafts  formed  between  flat  dies  are  very 
liable  to  be  split  in  this  way  when  not  carefully 
handled. 

The  faces  of  the  hammer-  and  anvil-dies  are  gen- 
erally of  the  same  width,  but  not  always  the  same 


128  FORGE-PRACTICE. 

length.  Thus,  when  the  hammer  is  resting  on  the 
anvil,  the  front  and  back  sides  of  the  two  dies  are 
in  line  with  each  other,  while  either  one  or  both 
ends  of  the  anvil-die  project  beyond  the  ends  of 
the  hammer-die. 

This  is  not  always  the  case,  however,  as  in  many 
hammers  the  faces  of  the  two  dies  are  the  same 
shape  and  size. 

Having  one  die  face  longer  than  the  other  is  an 
advantage  sometimes  when  a  shoulder  is  to  be 
formed  on  one  side  of  the  work  only. 

When  a  shoulder  is  to  be  formed  on  both  sides  of 
a  piece  the  work  should  be  placed  under  the  ham- 
mer in  such  a  way  that  the  top  die  will  work  in  one 
shoulder,  while  the  bottom  die  is  forming  the  other ; 
in  other  words,  the  work  should  be  done  from  the 
side  of  the  hammer,  where  the  edges  of  the  dies  are 
even,  as  shown  in  Fig.  188.  If  the  shoulder  is  re- 
quired on  one  side  only,  as  in  forging  tongs,  the 


L  A 


FIG.  188.  FIG.  189. 

work  should  be  so  placed  as  to  work  in  the  shoulder 
with  the  top  die,  while  the  bottom  die  keeps  the 
under  side  of  the  work  straight,  as  in  Fig.  189,  A. 


STEAM-HAMMER    WORK. 


129 


The  same  object,  a  shoulder  on  one  side  only, 
may  be  accomplished  by  using  a  block,  as  shown 
at  B,  Fig.  189.  The  block  may  be  used  as  shown, 
or  the  positions  of  work  and  block  may  be  reversed 
and  the  work  laid  with  flat  side  on  the  anvil  and 
block  placed  on  top. 

This  method  of  forming  shoulders  will  be  taken 
up  more  in  detail  in  treating  individual  forgings. 

Tools:  Swages. — In  general,  the  tools  used  in 
steam-hammer  work,  except  in  special  cases,  are 
very  simple. 

Swages  for  finishing  work  up  to  about  3"  or  4" 
in  diameter  are  commonly  made  as  shown  in  Fig. 
190.  The  two  parts  of  the  swage  are  held  apart 


FIG.  190. 

by  the  long  spring  handle.  This  spring  handle 
may  be  made  as  shown  at  B,  by  forming  it  of  a  sep- 
arate piece  of  stock  and  fastening  it  to  the  swage, 
by  making  a  thin  slot  in  the  side  of  the  block  with 
a  hot-chisel  or  punch,  forcing  the  handle  into  this 
and  closing  the  metal  around  it  with  a  few  light 
blows  around  the  hole  with  the  edge  of  a  fuller. 

Another  method  of  forming  the  handle  (C)  is  to 
draw  out  the  same  piece  from  which  the  blocks  are 


130 


FORGE-PRACTICE. 


made,  hammering  down  the  center  of  the  stock  to 
form  the  handle,  and  leaving  the  ends  full  size  to 
make  the  swages. 

Swages  for  large  work  are  made  sometimes  as 
shown  in  Fig.  191.     The  one  shown  at  B  is  made 


FIG.  191. 

for  an  anvil-die  having  a  square  hole,  similar  to 
the  hardie-hole  in  an  ordinary  anvil,  near  one  end. 
The  horn  on  the  swage,  at  x,  slips  into  this  hole, 
while  the  other  two  projections  fit,  one  on  either 
side,  over  the  sides  of  the  anvil.  These  horns,  or 
fingers,  prevent  the  swage  from  slipping  around 
when  in  use. 


END-VIEW 


FIG.  192. 

Tapering  and  Fullering  Tool. — As  the  faces  of  the 
anvil-  and  hammer-dies  are  flat  and  parallel,  it 
is  not  possible  to  finish  smoothly  between  the  bare 
dies,  any  work  having  tapering  sides. 


STEAM-HAMMER   WORK.  13! 

By  using'  a  tool  similar  to  the  one  shown  in  Fig. 
192  tapering  work  may  be  smoothly  finished. 

Taper  Work. — The  use  of  the  tool  illustrated 
above  is  shown  in  Fig.  193.  For  roughing  out 
taper  work,  the  tool  is  used  with  the  curved  side 


ROUGKING  FINISHING 

FIG.  193. 

down,  the  straight  side  being  flat  with  the  hammer- 
die.  When  finishing  the  taper,  the  tool  is  reversed, 
the  flat  side  being  held  at  the  desired  angle  and 
the  hammer  striking  the  curved  side..  This  curved 
side  enables  the  tool  to  do  good  work  through 
quite  a  wide  range  of  angles.  If  too  great  an  angle 
is  attempted,  the  tool  will  be  forced  from  under 
the  hammer  by  the  wedging  action. 

Fullers. — Fullers  such  as  used  for  ordinary  hand 
forgings  are  very  seldom  employed  in  steam-ham- 
mer work.  To  take  their 
place  simple  round  bars 
are  used.  When  much 
used,  the  bars  should  be 
of  tool-steel. 

One  use  of  round  bars, 
as  mentioned  above,  is  il- 
lustrated in  Fig.  194.  Here  the  work,  as  shown,' 


132  FORGE-PRACTICE. 

has  a  semicircular  groove  extending  around  it, 
forming  a  "neck."  The  groove  is  formed  by  plac- 
ing a  short  piece  of  round  steel  of  the  proper  size 
on  the  anvil-die;  on  this  is  placed  the  work,  with 
the  spot  where  the  neck  is  to  be  formed  directly 
on  top  of  the  bar.  Exactly  above  the  bar,  and 
parallel  to  it  on  top  of  the  work,  is  held  another  bar 
of  the  same  diameter.  By  striking  with  the  hammer, 
the  bars  are  driven  into  the  work,  forming  the 
groove.  The  work  should  be  turned  frequently 
to  insure  a  uniform  depth  of  groove  on  all  sides; 
for,  if  held  in  one  position,  one  bar  will  work  in 
deeper  than  the  other. 

Adjusting  Work  Under  the  Hammer. — When  work 
is  first  laid  on  the  anvil  the  hammer  should 
always  be  lowered  lightly  down  on  it  in  order  to 
properly  "locate"  it.  This  brings  the  work  flat 
and  true  with  the  die-faces;  and  if  held  in  this 
position  (and  care  should  be  taken  to  see  that  it  is) , 
there  will  be  little  chance  of  the  jumping,  jarring, 
and  slipping,  caused  by  holding  the  forging  in  the 
wrong  position.  This  is  particularly  true  when 
using  tools,  as  great  care  must  be  taken  to  see  that 
the  hammer  strikes  them  fairly.  If  the  first  blow 
is  a  heavy  one,  and  the  work  is  not  placed  exactly 
right,  there  is  danger  of  the  piece  flying  from  under 
the  hammer  and  causing  a  serious  accident. 

As  an  illustration  of  the  above,  suppose  that  a 
piece  be  carelessly  placed  on  the  anvil,  as  shown  ifi 
Fig.  195,  the  piece  resting  on  the  edge  of  the  anvil 
only,  not  flat  on  the  face,  as  it  should. 

When  the  hammer  strikes  quickly  and  hard  two 


STEAM-HAMMER   WORK.  133 

things  may  happen :  either  the  bar  will  be  bent  (as 
it  will  if  very  hot  and  soft)  or 
it  will  be  knocked  into  the  posi- 
tion shown  by  the  dotted  lines. 
If  the  hammer  be  lowered  lightly 
at  first,  the  bar  will  be  pushed 
down  flat,  and  assumes  the  dotted 
position  easily,  where  it  may  be 
held  for  the  heavy  blows. 

Squaring  Up  Work.  —  It  frequently  happens  in 
hammer  work,  as  well  as  in  hand  forging,  that  a 
piece  which  should  be  square  in  section  becomes 
lopsided  and  diamond-shaped. 

To  correct  this  fault  the  forging  should  be  held 
as  shown  in  Fig.  196,  with  the  long  diagonal  of 


M  D  O 

O'oo 


FIG.  196. 

the  diamond  shape  perpendicular  to  the  face  of  the 
anvil. 

A  few  blows  will  flatten  the  work  into  the  shape 
shown  at  B ;  the  work  should  then  be  rolled  slightly 
in  the  direction  of  the  arrow  and  the  hammering 
continued,  the  forging  taking  the  shape  of  C,  and, 
as  the  rolling  and  hammering  are  continued,  finally, 
the  square  section  D. 

Making  Small  Tongs. — As  an  example  of  manipu- 


FORGE-PRACTICE. 


lation  under  the  hammer,  the  making  of  a  pair  of 
ordinary  flat- jawed  tongs  is  a  good  illustration. 

Fig.  197  shows  the  different  steps  from  the  straight 
stock  to  the  finished  piece. 


FIG.  197. 

The  stock  is  heated  to  a  high  heat  and  bent  as 
shown  in  Figs.  198  and  199.     A  and  B  (Fig.  198) 

I 1 


\     / 


\ 


FIG.  199. 

are  two  pieces  of  flat  iron  of  the  same  thickness. 
The  stock  is  placed  like  Fig.  198,  the  hammer 
brought  down  lightly,  to  make  sure  that  every- 
thing is  in  the  proper  position,  and  then  one  hard 
blow  bends  the  stock  into  shape  (Fig.  199). 

Fig.   200  shows  the  method  of  starting  the  eye 


STEAM-HAMMER    WORK.  135 

and  working  in  the  shoulder.  The  bent  piece  is 
laid  flat  on  the  anvil  and  a  piece  of  flat  steel  laid  on 
top,  in  such  a  position  that  one  side  of  the  steel 
will  cut  into  the  work  and  form  the  shoulder  for 


FIG.  200. 


the  jaw  of  the  tongs.  The  steel  is  pounded  into 
the  work  until  the  metal  is  forged  thin  enough  to 
form  the  eye.  This  leaves  the  work  in  the  shape 
shown  in  Fig.  201.  The  part  A,  Fig.  201,  is  after- 
ward drawn  out  to  form  the  handle,  the  jaw  and 
eye  are  formed  up,  and,  lastly,  the  eye  is  punched. 
The  forming  of  the  jaw  and  the  punching  of  the 
rivet-hole  should  be  done  with  the  hand-hammer, 
and  not  under  the  steam-hammer. 

The  handle  is,  of  course,  drawn  out  under  the 
steam-hammer,  but  needs  no  particular  descrip- 
tion. For  careful  finishing,  the  taper  tool  illus- 
trated in  Fig.  192,  may  be  used,  or  a  sledge  and 
swages. 

As  a  general  thing,  steam-hammer  work  does  not 
differ  very  much  from  forging  done  on  the  anvil. 
The  method  of  operation,  in  either  case,  is  almost 
the  same;  but,  when  working  under  the  hammer, 
the  work  is  more  quickly  done  and  should  be  han- 
dled more  rapidly. 

Crank-shafts. — The     crank-shaft,  shown    in  Figs. 


i36 


FORGE-PRACTICE. 


128  and  129,  is  a  quite  common  example  of  steam- 
hammer  work. 

The  different  operations  are  about  the  same  as 
described  for  making  it  on  the  anvil. 

A  specially  shaped  tool  is  used  to  make  the  cuts 
each  side  of  the  crank  cheek.  This  tool  and  its 
use  are  shown  in  Fig.  202.  When  the  cuts  are 


FIG.  202. 


FIG.  203. 


very  deep,  they  should  first  be  made  with  a  hot- 
chisel  and  then  spread  with  the  spreading  tool. 
If  the  shoulder  is  not  very  high,  both  operations, 
of  cutting  and  spreading,  may  be  done  at  once  with 
the  spreading  tool. 

After  marking  and  opening  out  the  cuts,  the 
same  precautions,  to  avoid  cold-shuts,  must  be 
taken  as  are  used  when  doing  the  same  sort  of 
work  on  the  anvil.  The  work  should  be  held  and 
handled  much  the  same  as  illustrated  in  Fig.  131, 


STEAM-HAMMER   WORK.  137 

only  in  this  case  the  sledge  and  anvil  are  replaced 
by  the  top  and  bottom  dies  of  the  steam-hammer. 

A  block  of  steel  may  be  used  for  squaring  up  into 
the  shoulder,  as  shown  in  Fig.  203.  If  a  shoulder 
is  to  be  formed  on  both  sides,  one  block  may  be 
placed  below  and  another  above  the  work,  some- 
what as  shown  before  in  Fig.  194;  the  round  bars 
in  the  illustration  being  replaced  with  square  ones. 

Knuckles. — A  knuckle  such  as  shown  in  Fig. 
139  would  be  made  by  identically  the  same 
process  as  described  for  making  it  on  the  anvil. 
A  few  suggestions  might  be  made,  however. 

After  the  end  of  the  bar  has  been  split  and  bent 
apart,  ready  for  shaping,  the  work  should  be  han- 
dled, under  the  hammer,  as  shown  in  Fig.  204.  It 


FIG.  204. 

should  first  be  placed  as  shown  by  the  solid  lines, 
and  as  the  hammering  proceeds,  should  be  gradually 
worked  over  into  the  position  shown  by  the  dotted 
lines.  The  other  side  is  worked  in  the  same  way. 


138  FORGE-PRACTICE. 

After  drawing  out  and  shaping  the  ends  the 
knuckle  is  finished  by  bending  the  ends  together 
over  a  block,  in  the  same  way  as  shown  in  Fig.  144, 
the  work  being  done  under  the  hammer. 

Connecting-rod.  Drawing  Out  between  Shoulders. — 
The  forging  illustrated  in  Fig.  126,  while  hardly 
the  exact  proportions  of  common  connecting- 
rods,  is  near  enough  the  proper  shape  to  be  a  good 
example  of  that  kind  of  forging. 

The  forging,  after  the  proper  stock  calculation 
has  been  made,  is  started  by  making  the  cuts  near 
the  two  ends,  as  shown  in  Fig.  127.  The  distance, 
A,  must  be  so  calculated,  as  explained  before,  that 


FIG.  205.  FIG.  206. 

the  stock  represented  by  that  dimension,  when 
drawn  out,  will  form  the  shape,  2"  in  diameter  and 
24"  long,  connecting  the  two  wide  ends. 

The  cuts  are  made  with  the  spreading  tool  used 
in  connection  with  a  short  block  shaped  the  same 


STEAM-HAMMER   WORK.  139 

as  the  tool,  or  a  second  tool,  the  tools  being  placed 
one  above  and  one  below  the  work,  as  shown  in 
Fig.  205. 

After  making  the  cuts  the  stock  between  them  is 
drawn  down  to  the  proper  size  and  finished. 

It  sometimes  happens  that  the  distance  A  is  so 
short  that  the  cuts  are  closer  together  than  the 
width  of  the  die-faces,  thus  making  it  impossible 
to  draw  out  the  work  by  using  the  flat  dies.  This 
difficulty  may  be  overcome  by  using  two  narrow 
blocks  as  shown  in  Fig.  206. 

Weldless  Rings — Special  Shapes. — It  is  often  nec- 
essary to  make  rings  and  similar  shapes  without  a 
weld.  The  simple  process  is  illustrated  in  Figs. 
155-7.  Rings  may  be  made  in  this  way  under  the 
steam-hammer  much  more  rapidly  than  is  possible 
by  bending  and  welding.  To  illustrate  the  rapid- 
ity with  which  weldless  rings  can  be  made,  the 
author  has  seen  the  stock  cut  from  the  bar,  the 
ring  forged  and  trued  up  in  one  heat.  The  ring  in 
question  was  about  10"  outside  diameter,  the  section 
of  stock  in  rim  being  about 
i"  square.  The  stock  used 
was  about  3"  square,  soft  steel. 

A  forging  for  a  die  to  be 
made  of  tool-steel  is  shown  in 
Fig.  207.  FlG-  2°7- 

This  is  made  in  the  same  general  way  as  weld- 
less  rings.  The  stock  is  cut,  shaped  into  a  disc, 
punched,  and  worked  over  a  mandril  into  the  shape 
shown  at  A,  Fig.  208. 

The  lug,  projecting  toward  the  center  from  the 


140 


FORGE-PRACTICE. 


flat  edge  of  the  die,  is  shaped  on  a  special  mandril, 
the  work  being  done  as  shown  at  B,  the  thick  side 


FIG.  208. 


of  the  ring  being  driven  into  the  groove  in  the  man- 
dril and  shaped  up  as  shown  at  C,  where  the  end 
view  of  the  mandril  and  ring  is  shown. 

If  the  flat  edge  of  the  die  is  very  long,  it  may  be 
straightened  out  by  using  a  flat  mandril  and  work- 


FIG.  209. 

ing  each  side  of  the  projecting  lug  after  the  lug  has 
been  formed. 


STEAM-HAMMER    WORK.  141 

The  forging  leaves  the  hammer  in  the  shape 
shown  in  Fig.  209  at  A.  The  finishing  of  the  sharp 
corner  is  done  on  the  anvil  with  hand  tools,  in 
much  the  same  way  that  any  corner  is  squared  up, 
Figs.  B  and  C  giving  a  general  idea  of  working  up 
the  corner  by  using  a  flatter. 

Punches. — The  punches  used  for  this  kind  of 
work,  and  in  fact  for  all  punching  under  the  steam- 
hammer,  should  be  short  and  thick. 

A  punch  made  as  shown  in  Fig.  210  is  very  satis- 
factory for  general  work.  This  punch  is  simply 
a  short  tapering  pin  with  ^rf^^> 

a    shallow    groove    formed     ^-\^z^^^^ 
around  it  about  one  third        — j 
of  the  length  from  the  big      I     I 
end.       A     bar     of     small 

1       •  /i/r      •  1_  FlG-  2I0' 

round    iron    (f      is    about 

right  for  small  punches)  is  heated,  wrapped  around 

the  punch  in  the  groove  and  twisted  tight,  as  shown. 

The  punching  is  done  in  exactly  the  same  way 
as  with  hand  tools ;  that  is,  the  punch  is  driven  to 
a  depth  of  about  one  half  or  two  thirds  the  thick- 
ness of  the  piece,  with  the  work  lying  flat  on  the 
anvil;  the  piece  is  then  turned  over,  the  punch 
started  with  the  work  still  flat  on  the  anvil,  and 
the  hole  completed  by  placing  a  disc,  or  some  other 
object  with  a  hole  in  it,  on  the  anvil;  on  this  the 
work  is  placed  with  the  hole  in  the  disc  directly 
under  where  the  punch  will  come  through.  The 
punch  is  then  driven  through  and  the  hole  completed. 

The  end  of  the  punch  must  not  be  allowed  to 
become  red-hot.  If  the  punch  is  left  in  contact 


142  FORGE-PRACTICE. 

with  the  work  too  long,  it  will  become  heated,  and, 
after  a  few  blows,  the  end  will  spread  out  in  a  mush- 
room shape  and  stick  in  the  hole. 

To  prevent  the  above,  the  punch  should  be  lifted 
out  of  the  hole  and  cooled  between  every  few  blows. 

Sometimes,  when  a  hole  can  be  accurately  lo- 
cated, an  arrangement  like  that  shown  jn  Fig.  211 
is  used.  The  punch  in  this  case  is  only  slightly 
longer  than  the  thickness  of  the  piece  to  be  pierced, 
and  is  used  with  the  big  end  down  as  shown. 


FIG.  211.  FIG.  212. 

The  punch  is  driven,  together  with  the  piece  of 
metal  which  is  cut  out,  through  into  the  hole  in  the 
die,  which  is  just  enough  larger  to  give  clearance  to 
the  punch. 

A  convenient  arrangement  for  locating  the  punch 
centrally  with  the  hole  in  the  die  is  shown  in  Fig. 
212. 

The  die  should  be  somewhat  larger  in  diameter 
than  the  work  to  be  punched.  The  work  is  first 
placed  in  the  proper  position  on  the  die  and  the 
punch  placed  on  top.  The  punch  is  located  by 
using  a  spider-shaped  arrangement  made  from  thin 
iron.  This  spider  has  a  central  ring  with  a  hole  in 
the  center  large  enough  to  slip  easily  over  the 
punch.  Radiating  from  the  ring  are  four  arms, 
three  of  which  have  their  ends  bent  down  to  fit 


STEAM-HAMMER  WORK.  143 

around  the  outside  of  the  die,  the  fourth  being 
longer  and  used  for  a  handle.  The  ends  of  the  bent 
arms  are  so  shaped  that  where  they  touch  the  out- 
side of  the  die  the  central  hole  is  exactly  over  the 
hole  in  the  die. 

After  locating  the  punch  with  the  spider,  and 
while  the  spider  is  still  in  place,  a  light  blow  of  the 
hammer  starts  the  punch,  after  which  the  spider  is 
lifted  off  and  the  punch  driven  through. 

Forming  Bosses  on  Flanges,  etc. — A  boss,  on  a 
flange  or  other  flat  piece,  such  as  shown  in  Fig.  213, 
may  be  very  easily  formed  by  using  a  few  simple 


FIG.  213.  FIG.  214. 

tools.  The  special  tools  are  shown  in  Fig.  214, 
and  are :  a  round  cutter  used  for  starting  the  boss, 
shown  at  A,  which  also  shows  a  section  of  the  tool, 
and  a  flat  disc,  shown  at  B,  used  for  flattening 
and  finishing  the  metal  around  the  boss. 

The  stock  is  first  forged  into  shape  slightly 
thicker  than  the  boss  is  to  be  finished,  as  it  flattens 
down  somewhat  in  the  forging. 

The  boss  is  started  by  making  a  cut  with  the 
circular  cutter,  as  shown  at  A,  Fig.  215,  where  is 
also  shown  a  section  of  the  forging  after  the  cut 
has  been  mad?. 


144 


FORGE-PRACTICE. 


The  metal  outside  of  the  cut  is  then  flattened 
out,  as  shown  by  the  dotted  lines.     This  flattening 


FIG.  215. 

and  drawing  out  may  be  done  easily  by  using  a 
bar  of  round  steel,  as  shown  at  C.  The  bar  is 
placed  in  such  a  position  as  to  fall  just  outside  of 
the  boss.  After  striking  a  blow  with  the  hammer, 
the  bar  is  moved  farther  toward  the  edge  of  the 
work  and  the  piece  is  turned  slightly.  In  this  way 
the  stock  is  roughly  thinned  out,  leaving  the  boss 
standing.  To  finish  the  work,  the  forging  is  turned 
bottom  side  up  over  the  disc>  with  the  boss  extend- 
ing down  into  the  hole  in  the  disc,  as  shown  at  B. 
With  a  few  blows,  the  disc  is  forced  up  around  the 
boss  and  finishes  the  metal  off  smoothly. 

The  disc  need  not  necessarily  be  large  enough  to 
extend  to  the  edge  of  the  work;  for  if  a  disc  as 
described  above  is  used  to  finish  around  the  boss, 
the  edge  of  the  work  may  be  drawn  down  ;n  the 
usual  way  under  the  hammer. 

A  disc  is  not  absolutely  necessary  in  any  case; 
but  the  work  may  be  more  carefully  and  quickly 
finished  in  this  way. 


STEAM-HAMMER  WORK.  145 

Round  Tapering  Work. — A  round  tapering  shape, 
such   as    shown  at    .4,    Fig.    216,    should  be  first 


i  c=\   B 

FIG.  216. 

roughly  forged  into  shape.  It  may  be  started  by 
working  in  the  shoulder  next  the  head  with  round 
bars,  in  the  way  illustrated  before  in  Fig.  194. 

The  roughing  out  may  be  done  with  square  or 
flat  pieces,  using  them  in  much  the  same  way;  or 
one  piece  only  may  be  used  and  the  work  allowed 
to  lie  flat  on  the  anvil,  with  the  head  projecting 
over  the  edge. 

After  roughing  out,  the  work  may  be  finished 
with  swages.  As  ordinarily  used,  the  swages 
would  leave  the  forging  straight,  with  the  oppo- 
site sides  parallel.  To  form  a  taper,  a  thin  strip 
should  be  held  on  top  of  the  upper  swage  close  to 
and  parallel  with  one  of  the  edges,  as  shown  at 
B,  Fig.  216.  The  strip  causes  the  swage  to  tip 
and  slant,  thus  forming  the  work  tapering. 


CHAPTER  VIII. 


DUPLICATE    WORK. 

WHEN  several  pieces  are  to  be  made  as  nearly 
alike  as  possible,  the  work  is  generally  more  easily 
done  by  using  ' '  dies"  or  '  *  jigs." 

Generally  speaking,  "dies"  are  blocks  of  metal 
having  faces  shaped  for  bending  or  forming  work. 
The  term  "jig"  may  be  applied  to  almost  any 
contrivance  used  for  helping  to  bend,  shape,  or 
form  work.  As  ordinarily  used,  a  jig,  generally, 
is  simply  a  combination  of  some  sort  of  form  or 

flat  plate  and  one  or  more 
clamps  and  levers  for  bend- 
ing. 

p^      :~~~~P:1  Dies,  or  jigs,  for  simple 

i — — — J^  bending  may  be  easily  and 

cheaply  made  of  ordinary 
cast  iron;  and,  for  most 
purposes,  left  rough,  or  un- 
finished. 

Simple  Bending.  -  The 
bend  shown  in  Fig.  217  is 
a  fair  example  of  simple 
work.  The  dies  for  making 
this  bend  are  two  blocks 


FIG.  217. 


of   cast   iron   made  as   shown,  one   simply  a    rect- 

146 


DUPLICATE    WORK.  147 

angular  block  the  size  of  the  inside  of  the  bend  to 
be  made,  the  other  a  block  having  on  one  side  a 
groove  the  same  shape  as  the  outside  of  the  piece 
to  be  bent.  The  blocks  should  be  slightly  wider 
than  the  stock  to  be  bent. 

The  stock  is  cut  to  the  proper  length,  heated, 
placed  on  the  hollow  block,  and  the  small  block 
placed  on  top,  as  shown  by  the  dotted  lines  at  B, 
Fig.  217.  The  bend  is  made  by  driving  down  the 
small  block  with  a  blow  of  the  hammer. 

Work  of  this  kind  may  be  easily  done  under  a 
steam-hammer;  and  the  dies  described  here  are 
intended  for  use  in  this  way,  most  of  them  having 
been  designed  for,  and  used  under,  a  200-lb.  ham- 
mer. 

Dies  of  this  kind  may  be  fitted  to  the  jaws  of  an 
ordinary  vise,  the  bending  being  done  by  tighten- 
ing up  the  screw. 

A  die  such  as  described  above  should  have  a 
little  ''clearance";  that  is,  the  opening  in  the  hol- 
low die  should  be  slightly  larger  at  the  top  than  at 
the  bottom.  The  small,  or  top,  die  should  be  made 
accordingly,  slightly  smaller  at  the  bottom. 

To  make  the  dies  easier  to  handle,  a  hole  may  be 
drilled  and  tapped  in  each  block  and  pieces  of 
round  bars  threaded  and  screwed  into  the  holes  to 
form  handles.  This  is  more  fully  described  in  the 
following  example: 

Fig.  218,  A,  is  a  hook  bent  from  stock  f  "  X  i",  to 
fit  around  the  flange  of  an  I  beam.  The  hooks 
were  about  6"  long  when  finished.  To  bend  these, 
two  cast-iron  blocks,  or  dies,  were  used,  shown  at 


148 


FORGE-PRACTICE. 


B.     The  dies  were  rough  castings.     Patterns  were 
made  by  laying  out  the  hook  on  a  piece  of  2"  white 


FIG.  218. 


FIG.  219. 


pine  and  then  sawing  to  shape  with  a  band-saw. 
The  block  was  "laid  off"  as  shown  in  Fig.  219,  A, 
the  sawing  being  done  on  the  dotted  lines.  This 
left  the  blocks  of  such  a  shape  that  the  space  be- 
tween them,  when  they  were  brought  together 
with  the  upper  and  lower  edges  parallel,  was  just 
equal  to  the  thickness  of  the  stock  to  be  bent. 

Patterns  of  this  kind  should  be  given  plenty  of 
"draft,"  which  may  be  quickly  and  easily  done  by 
planing  the  sides,  after  the  blocks  are  sawed  out, 
to  taper  slightly  as  shown  in  Fig.  219,  B,  where  the 
dotted  lines  show  the  square  sides  before  being 
planed  off  for  draft  as  indicated  by  the  solid  lines. 

When  the  castings  were  made,  a  13/32//  hole  was 
drilled  in  the  right-hand  end  of  each  block  and 
tapped  with  \"  tap.  A  piece  of  \"  round  iron 
about  30"  long  was  threaded  with  a  die  for  about 
ij"  on  each  end  and  bent  up  to  form  the  handle. 


DUPLICATE   WORK.  149 

A.  nut  was  run  on  each  end  and  the  blocks  screwed 
on  and  locked  by  screwing  the  nut  up  against  them, 
making  the  finished  dies  as  shown  in  Fig.  218.  The 
handle  formed  a  spring,  holding  the  dies  far  enough 
apart  to  allow  the  iron  to  be  placed  between 
them. 

As  mentioned  before,  dies  of  this  kind  can  be 
easily  made  to  cover  a  variety  of  work,  and  are 
very  inexpensive.  The  dies  in  question,  for  in- 
stance, required  about  half  an  hour's  pattern  work, 
and  about  as  much  time  more  to  fit  the  handles. 
Calculating  shop  time  at  50  cents  per  hour  and 
castings  at  5  cents  per  pound,  and  allowing  for  the 
handle,  the  entire  cost  of  these  dies  was  less  than 
$1.25. 

The  same  handle  can  be  used  for  any  number  of 
dies  of  about  the  same  size,  and  if  any  one  of  these 
dies  should  break,  it  can  be  replaced  at  a  very 
trifling  cost. 

Cast-iron  dies  of  this  character  will  bend  several 
hundred  pieces  and  show  no  signs  of  giving  out, 
although  they  may  snap  at  the  first  piece  if  made 
of  hard  iron.  On  an  important  job  it  is  generally 
wise  to  cast  an  extra  set  to  have  in  case  the  first 
prove  defective. 

Almost  any  simple  shape  may  be  bent  in  this 
way,  and  the  dies  may  be  used  on  any  ordinary 
steam-hammer  with  flat  forging  faces ;  and  not  only 
that,  but,  not  having  to  be  fastened  down  in  any 
way,  they  may  be  placed  under  the  hammer,  or 
removed,  without  interfering  with  other  work. 

Loop  with  Bent-in  Ends. — For    larger   work,  it  is 


FORGE-PRACTICE. 


often  better  to  have  a  die  to  replace  the  lower  die 
of  the  hammer,  as  in  the  case  mentioned  below. 

A  number  of  forgings  were  wanted  like  A,  Fig. 
220.      The  stock  was  cut  to  the  proper  length  and 


FIG.  220. 

the  ends  bent  at  right  angles.  To  make  all  the 
pieces  alike,  one  end  of  each  piece  was  first  bent, 
as  shown  at  B,  in  a  vise.  The  other  ends  of  the 
pieces  were  then  all  bent  the  same  way,  by  hooking 
the  bent  end  over  a  bar  cut  to  the  proper  length 
and  bending  down  the  straight  end  over  the  other 
end  of  the  bar,  as  shown  at  C.  To  make  the  final 
bend,  a  cast-iron  form  was  used  similar  to  D.  This 
casting  was  about  2\"  thick,  and  the  dovetail- 
shaped  base  fitted  the  slot  in  the  anvil  base  of  the 
hammer.  When  the  form  was  used,  the  anvil-die 
was  removed  and  the  form  put  in  its  place. 

The  strips  to  be  bent  were  laid  on  top  of  this  form 
and  a  heavy  piece  of  flat  stock,  i"X2",  bent  into 


DUPLICATE    WORK. 


IS1 


a  U  shape  to  fit  the  outside  of  the  forging,  placed 
on  top.  A  light  blow  of  the  hammer  would  force 
the  U-shaped  piece  down,  bending  the  stock  into 
the  proper  shape.  Fig.  221  shows  the  operation, 
the  dotted  lines  indicat- 
ing the  position  of  the 
pieces  before  bringing 
down  the  hammer. 

The  most  satisfactory 
results  were  obtained 
by  bringing  the  ham- 
mer down  lightly  on 
the  work,  then,  by  turn- 
ing on  a  full  head  of 
steam,  the  ram  was 
forced  down  compara- 
tively slowly,  bending 
the  stock  gradually  and  ' 
easily.  This  was  much 
more  satisfactory  than  a  quick,  sharp  blow. 

It  is  not  necessary  to  have  the  U-shaped  piece  of 
exactly  the  same  shape  as  the  forging.  It  is  suffi- 
cient if  the  lower  ends  of  the  U  are  the  proper  dis- 
tance apart.  As  the  strip  is  bent  over  the  form,  it 
naturally  follows  the  outline;  and  it  is  only  neces- 
sary to  force  it  against  the  form  at  the  lower  points 
of  the  sides. 

The  last  bend  might  have  been  made  by  using  a 
second  die  fastened  to  the  ram  of  the  hammer  in 
place  of  the  U-shaped  loop. 

Two  dies  are  necessary  for  much  work ;  but  these 
are  more  expensive  to  make.  The  upper  die  can 


FIG.  221. 


FORGE-PRACTICE. 


be  easily  made  to  fit  in  the  dovetail  on  the  ram  and 
be  held  in  place  with  a  key. 

Right-angle  Bending. — Very  convenient  tools  for 
bending  right  angles,  in  stock  \"  or  less  in  thick- 
ness, are  shown  in  Fig.  222.  The  lower  one  is  made 

to  fit  easily  over  the  anvil 
of  the  steam-hammer,  the 
projecting  lips  on  either 
side  preventing  the  die 
from  sliding  forward  or 
back.  The  upper  one  has 
a  handle  screwed  in,  as 
described  before.  Both 
of  these  bending  tools  are 
made  of  cast  iron,  the 
patterns  being  simply 
sawed  from  a  2"  plank. 

Cast-iron  dies  of  this 
kind  should  be  made  of  a  tough,  gray  iron,  rather 
than  the  harder  white  iron,  as  they  are  less  liable  to 
break  if  cast  from  the  former. 

Many  of  the  regular  hammer  dies,  that  is,  the  dies 
with  flat  faces  for  general  forging,  are  made  of  cast 
iron ;  but  the  iron  in  this  case  is  of  another  quality 
—chilled  iron — the  faces  being  chilled,  or  hardened, 
for  a  depth  of  an  inch  or  more. 

Circular  Bending — Coil  Springs. — The  dies  de- 
scribed before  have  been  for  simple  bends;  the 
blows,  or  bending  force,  coming  from  one  direction 
only.  In  the  following  example,  where  a  complete 
circle,  or  more  than  a  circle,  is  formed,  an  arrange- 
ment of  a  different  nature  is  required. 


FIG.  222. 


DUPLICATE    WORK. 


153 


The  spring  shown  in  Fig.  223  is  an  example  of 
this  kind.  In  this  particular  case  the  bending 
was  done  cold;  but  for  hot  bending  the  operation 
is  exactly  the  same. 


FIG.  223. 


FIG.  224. 


This  jig  (Fig.  224)  was  built  upon  a  base-plate,  A, 
about  f  "  thick,  having  one  end  bent  down  at  right 
angles  for  clamping  in  an  ordinary  vise. 

The  post  E  was  simply  a  i"  stud  screwed  into 
the  plate.  B  was  a  piece  of  f'Xi"  stock  about 
2"  long,  fastened  down  with  two  rivets,  and  served 
as  a  stop  for  clamping  the  stock  against  while  bend- 
ing. C  was  a  lever  made  of  a  piece  of  J"Xi" 
stock  about  10"  long,  having  one  end  ground 
rounding  as  shown.  This  lever  turned  on  the 
screw  Fy  threaded  into  the  base-plate.  D  was  the 
bending  lever,  having  a  hole  punched  and  forged 
in  the  end  large  enough  to  turn  easily  on  the  stud 
E.  On  the  under  side  of  this  lever  was  riveted  a 
short  piece  of  iron  having  one  end  bent  down  at 
right  angles.  This  piece  was  so  placed  that  the 
distance  between  stud  E  and  the  inside  face  of  bent 
end,  when  the  lever  was  in  position  for  bending,  was 


154  FORGE-PRACTICE. 

about  Ye/'  greater  than  the  thickness  of  the  stock 
to  be  bent. 

When  in  operation,  the  stvjck  to  be  bent  was 
placed  in  the  position  shown  in  the  sketch,  the 
lever  C  pulled  over  to  lock  it  in  place,  and  the  bend- 
ing lever  D  dropped  over  it  in  the  position  shown. 
To  bend  the  stock,  the  lever  was  pulled  around  in 
the  direction  of  the  arrow  and  as  many  turns  taken 
as  were  wanted  for  the  spring,  or  whatever  was 
being  bent.  By  lifting  off  the  bending  lever  and 
loosening  the  clamping  lever  the  piece  could  be 
slipped  from  the  stud. 

With  jigs  of  any  kind  a  suitable  stop  should 
always  be  provided  to  place  the  end  of  the  stock 
against,  in  order  to  insure  placing  and  bending  all 
pieces  as  nearly  as  possible  alike. 

Drop-forgings.  —  Strictly  speaking,  drop-forgings 
are  forgings  made  between  dies  in  a  drop-press  or 
forge.  Each  die  has  a  cavity  in  its  face,  so  shaped 
that  when  the  dies  are  in  contact  the  hole  left  has 
the  form  of  the  desired  forging.  One  of  the  dies  is 
fastened  to  the  bed  of  the  drop-press,  directly  in 
line  with  and  under  the  other  die,  which  is  keyed 
to  the  under  side  of  the  drop,  a  heavy  weight  run- 
ning between  upright  guides.  The  forging  is  done 
by  raising  the  drop  and  allowing  it  to  fall  between 
the  guides  of  its  own  weight. 

There  are  generally  two  or  more  sets  of  cavities 
in  the  die-faces,  one  set  being  used  for  roughing 
out,  or  "breaking  down,"  the  stock  roughly  to 
shape ;  another  set  for  finishing. 

The  dies  mentioned  above  would  be  known  as 


DUPLICATE    WORK.  155 

the  "breaking-down"  and  "finishing"  dies,  re- 
spectively. Sometimes  several  intermediate  dies 
are  used. 

In  a  general  way,  the  term  drop-forging  may  be 
used  to  describe  almost  any  forging  formed  be- 
tween shaped  dies  whether  made  by  a  drop-press  or 
other  means. 

Taking  the  word  in  its  broadest  meaning,  the 
example  given  below  might  be  called  a  drop-forg- 
ing, the  work  being  done  between  shaped  dies. 

Eye-bolt  —  Drop-forging.  —  The  example  in  ques- 
tion is  the  eye-bolt  given  in  Fig.  225.  The  differ- 
ent steps  in  the  making,  and 
the  dies  used,  are  shown  in  Fig. 
226. 

Round  stock  is  used,  and  first 
shaped  like  A,  Fig.  226,  the 
forming  being  done  in  the  die 

B.     This  die,  as  well  as  the  other 

-       .  FIG.  225. 

one,  is  made   in  the  same  way 

as  ordinary  steam-hammer  swages ;  that  is,  simply 
two  blocks  of  tool-steel  fastened  together  with  a 
spring  handle.  The  inside  faces  of  the  blocks  are 
formed  to  shape  the  piece  as  shown. 

The  stock  is  revolved  through  about  90  degrees 
between  each  two  blows  of  the  steam-hammer,  and 
the  hammering  continued  until  the  die-faces  just 
touch. 

For  the  second  step  the  ball  is  flattened  to  about 
the  thickness  of  the  finished  eye  between  the  bare 
hammer-dies.  The  hole  is  then  punched,  under 
the  hammer,  with  an  ordinary  punch. 


156 


FORGE-PRACTICE. 


The  forging  is  finished  with  a  few  blows  in  the 
finishing  die  D,  which  is  shown  by  a  sectional  cut 
and  plan.  This  die  is  so  shaped  that,  when  the 
two  parts  are  together,  the  hole  left  is  exactly  the 


SECTION  AT  X-X 


FIG.  226. 

shape  of  the  finished  forging.  In  the  first  die,  how- 
ever, it  should  be  noticed  that  the  holes  do  not  con- 
form exactly  to  the  desired  shape  of  the  forging; 
here  the  holes,  instead  of  being  semicircular,  are 
rounded  off  considerably  at  the  edges.  This  is 
shown  more  clearly  in  Fig.  227,  A,  where  the  dotted 
lines  show  the  shape  of  the  forging,  the  solid  lines 
the  shape  of  the  die. 

The  object  of  the  above  is  this:  If  the  hole  is  a 
semicircle  in  section,  the  stock,  being  larger  than 
the  small  parts  of  the  hole,  after  a  blow,  is  left 


DUPLICATE    WORK. 


157 


FIG.  227. 


like  B,  the   metal  being   forced   out   between   the 

flat  faces  of  the  die  and 

forming     'fins.'       When 

the    bar   is    turned    and 

again    hit,  these  fins  are 

doubled   in  and  make    a 

bad  place  in  the  forging. 

When  the  hole  is  a 
modified  semicircle,  as  de- 
scribed above,  the  stock 
will  be  formed  like  C, 
and  may  be  turned  and 
worked  without  injury 
or  danger  of  cold-shuts. 

Forming  Dies  Hot. — Making  dies  for  work  of  the 
above  kind  is  generally  an  expensive  process,  par- 
ticularly if  the  work  be  done  in  the  machine-shop. 

Rough  dies  for  this  kind  of  work  may  be  cheaply 
made  in  the  forge-shop  by  forming  them  hot. 

The  blocks  for  the  dies  are  forged  and  prepared, 
and  a  blank,  or  'master,'  forging  the  same  shape 
and  size  as  the  forgings  the  dies  are  expected  to 
form  is  made  from  tool-steel  and  hardened. 

The  die  blanks  are  then  heated,  the  master 
placed  between  them,  and  the  dies  hammered  to- 
gether, the  master  being  turned  frequently  during 
the  hammering. 

This,  of  course,  leaves  a  cavity  the  shape  of  the 
master. 

When  two  or  more  sets  of  dies  are  necessary 
there,  of  course,  must  be  separate  masters  for  each 
set  of  dies.  Dies  made  in  this  way  will  have  the 


158  FORGE-PRACTICE. 

corners  of  the  cavities  rounded  off,  as  the  metal  is 
naturally  pulled  away  during  the  forming,  leaving 
the  corners  somewhat  relieved. 

Dies  such  as  described  above  may  be  used  to 
advantage  under  almost  any  steam-hammer. 

For  spring  hammers,  helve  hammers,  and  power 
hammers  generally  the  die  faces  may  be  formed 
the  same  as  above;  but  the  die-blocks  should  be 
fastened  to  the  hammer  and  anvil  of  the  power 
.hammer  itself,  replacing  the  ordinary  dies. 

Cast-iron  Dies. — Much  drop-forging  is  done  with 
cast  iron  dies,  and  for  rough  work  that  is  not  too 
heavy  they  are  very  satisfactory,  and  the  first  cost 
is  very  small  as  compared  with  the  steel  dies  used 
for  the  same  purpose. 

Drop-forging  can  be  done  in  this  way  with  the 
steam-hammer,  by  keying  the  dies  in  the  dovetails 
made  for  the  top  and  bottom  hammer-dies. 

Welding  in  particular  is  done  in  this  way,  as  the 
metal  to  be  worked  is  in  such  a  soft  condition  that 
there  is  little  chance  of  smashing  the  die. 


CHAPTER  IX. 

TOOL  FORGING  AND  TEMPERING. 

IT  is  assumed  that  the  general  method  of  tem- 
pering as  described  before  is  understood,  and  only 
special  directions  will  be  given  in  particular  cases 
in  the  following  pages. 

Forging  Heat. — Any  tool-steel  forging  on  which 
there  is  any  great  amount  of  work  to  be  done 
should  have  the  heavy  forging  and  shaping  done 
at  a  yellow  heat.  At  this  heat  the  metal  works 
easily  and  properly,  and  the  heavy  pounding  re- 
fines the  grain  and  leaves  the  steel  in  proper  condi- 
tion to  receive  a  cutting  edge.  When  a  tool  is 
merely  to  be  smoothed  off  or  finished,  or  forged  to 
a  very  slight  extent,  the  work  should  be  done  at  a 
much  lower  heat,  just  above  the  hardening  tem- 
perature. 

Very  little  hammering  should  be  done  at  any 
heat  below  the  hardening  temperature. 

Cold-chisels. — The  ordinary  cold-chisel  is  so  sim- 
ple in  shape  that  no  detail  directions  are  necessary 
for  forging.  The  stock  should  be  heated  to  a  yel- 
low heat  and  forged  into  shape  and  finished  as 
smooth  as  possible.  If  properly  forged  the  end,  or 
edge,  will  bulge  out,  like  Fig.  228.  This  should  be 
nicked  across  with  a  sharp  hot-chisel  (but  not  cut 


i6o 


FORGE-PRACTICE. 


off),  as  shown  at  C,  and  broken  off  after  the  tool 
has  been  hardened.     This  broken  edge  will  then 


FIG.  228. 

show  the  grain  and  indicate  whether  the  steel  has 
been  hardened  at  a  proper  temperature. 

When  hardening,  the  chisel  should  be  heated  red- 
hot  as  far  back  from  the  point  as  the  line  A,  Fig. 
229.  Great  care  must  be  taken  to  heat  slowly 
enough  to  heat  the  thicker  part  of  the 
chisel  without  overheating  the  point.  If 
the  point  does  become  too  hot,  it  should 
not  be  dipped  in  water  to  cool  off,  but 
allowed  to  cool  in  the  air  to  below  the 
hardening  heat  and  then  reheated  more 
carefully. 

When  the  chisel  has  been  properly  heated 
to  the  hardening  heat,  the  end  should  be 
hardened  in  cold  water  back  to  the  line  B, 
Fig.  235.  As  soon  as  the  end  is  cold  the 
chisel  should  be  withdrawn  from  the 
water  and  one  side  of  the  end  polished 
off  with  a  piece  of  emery  or  something 
of  that  nature,  as  described  before. 

The  part  of  the  chisel  from  A  to  B  will  be  still 
red-hot,  and  the  heat  from  this  part  will  gradually 


FIG.  229. 


TOOL   FORGING  AND   TEMPERING.  T6i 

reheat  the  point  of  the  tool.  As  the  metal  is  re- 
heated the  polished  surface  will  change  color,  show- 
ing at  first  yellow,  brown,  and  at  last  purple.  As 
soon  as  the  purple,  almost  blue  color  reaches  the 
nick  at  the  end,  the  chisel  should  again  be  cooled, 
this  time  completely.  The  waste  end  may  now  be 
snapped  off  and  the  grain  examined.  To  test  for 
proper  hardness,  try  the  end  of  the  chisel  with  a 
fine  file,  which  should  scratch  it  slightly.  If  the 
grain  is  too  coarse,  the  tool  should  be  rehardened 
at  a  lower  temperature,  while  if  the  metal  is  too 
soft,  it  should  be  rehardened  at  a  higher  tempera- 
ture. 

Cape-chisel. — The  cape-chisel,  illustrated    in  Fig. 
230,  is  used  for  cutting  grooves  and  working  at  the 


bottom  of  narrow  channels.  The  cutting  edge  A 
should  be  wider  than  any  part  of  the  blade  back  to 
B,  which  should  be  somewhat  thinner  in  order  that 
the  blade  may  "clear"  when  working  in  a  slot  the 
width  of  A. 

The  chisel  is  started  by  thinning  down  B  over 
the  horn  of  the  anvil,  as  shown  at  A,  Fig.  231.  The 
finishing  is  done  with  a  hammer  or  flatter  in  the 
manner  illustrated  at  B.  The  chisel  should  not 
be  worked  flat  on  top  of  the  anvil,  as  shown  at  C, 
as  this  knocks  the  blade  out  of  shape. 


162 


FORGE-PRACTICE. 


The  cape-chisel  is  tempered  the  same  as  a  cold- 
chisel. 


FIG.  231. 

Square-  and  Round-nose  Cape-chisels. — The  chisels 
are  started  in  the  same  way  as  an  ordinary  cape- 
chisel,  the  ends  being  left  somewhat  more  stubby. 

The  end  is  then  finished  round  or  square,  as 
shewn  in  Fig.  232,  and  tempered  the  same  as  a 
cold -chisel. 

Round-nose  cape-chisels  are  sometimes  used  to 
center  drills,  and  are  then  called  "centering" 
chisels. 

Lathe-tools  in  General. — The  same  general  forms 
of  lathe-tools  are  followed  in  nearly  all  shops;  but 
in  different  places  the  shapes  are  altered  somewhat 
to  suit  individual  tastes. 


TOOL   FORGING   AND   TEMPERING.  ^ 

Right-  and  Left-hand  Tools. — Such  tools  as  side 
tools,  diamond  points,  etc.,  are  generally  made  in 
pairs — that  is,  right-  and  left-handed.  If  a  tool  is 
made  with  the  cutting  edge  on  the  left-hand  side 
(as  the  tool  is  looked  at  from  the  top  with  the  shank 


FIG.  232. 

of  the  tool  nearest  the  observer),  it  would  be  called 
a  right-hand  tool.  That  is,  a  tool  which  begins  its 
cut  at  the  right-hand  end  of  the  piece  and  cuts 
towards  the  left  is  known  as  a  right-hand  tool; 
one  commencing  at  the  left-hand  end  and  cutting 
towards  the  right  would  be  known  as  a  left-hand 
tool. 

The  general  shape  of  right-  and  left-hand  tool? 
for  the  same  use  is  practically  the  same  excepting 
that  the  cutting  edges  are  on  opposite  sides. 

Round-nose  and  Thread  Tools.— Round-nose  and 
thread  tools  are  practically  alike,  the  difference 
being  in  the  grinding  of  the  end.  The  thread  tool 
is  sometimes  made  a  little  thinner  at  the  point. 

The  round-nose  tool,  Fig.  233,  is  so  simple  in 
shape  that  no  description  of  the  forging  is  neces- 
sary. Care  must  be  taken  to  have  proper  "  clear- 
ance." The  cutting  is  all  done  at  or  near  the 


164 


FORGE-PRACTICE. 


end,  and  the  sides  must  be  so  shaped  that  they 
"clear"  the  upper  edge  of  the  end.  In  other 
words,  the  upper  edge  of  the  shaped  end  must  be 


!A 


FIG.  233. 

wider  at  every  point  than  the  lower  edge,  as  shown 
by  the  section. 

For  hardening,  the  tool  should  be  heated  about 
as  far  as  the  line  A,  Fig.  234,  and  cooled  up  to  the 


FIG.  234. 

line  B.     Temper  color  of  scale  should  be  light  yel- 
low. 

Cutting-off  Tools.  —  Cutting-off  tools  are  forged 
with  the  blade  either  on  one  side  or  in  the  center  of 
the  stock.  The  easier  way  to  make  them  is  to  forge 


TOOL    FORGING   AND   TEMPERING.  ^5 

the  blade  with  one  side  flush  with  the  side  of  the 
tool.     A  tool  forged  this  way  is  shown  in  Fig.  235. 


FIG.  235. 

The  cutting  edge  is  the  extreme  tip  of  the  blade, 
and  the  cutting  is  done  by  forcing  the  tool  straight 
into  the  work,  the  edge  cutting  a  narrow  groove. 
The  only  part  of  the  tool  which  should  touch  the 
work  is  the  extreme  end,  or  cutting  edge;  there- 
fore the  .th'ckest  part  of  the  blade  must  be  the  cut- 
ting edge,  the  sides  gradually  tapering  back  in  all 
directions  and  becoming  thinner,  as  shown  in  the 
drawing,  A  being  wider  than  B. 

The  cutting  edge  should  be  slightly  above  the 
level  of  the  top  of  the  tool,  or,  in  other  words,  the 
blade  should  slant  slightly  upwards. 

The  clearance  angle  at  the  end  of  the  tool  is 
about  right  for  lathe-tools ;  but  for  plainer  tools  the 
end  should  be  made  more  nearly  square,  about  as 
shown  by  the  line  X — X. 

For  hardening,  the  heat  should  extend  to  about 
the  line  C — C,  and  the  end  should  be  cooled  to 
about  the  line  D — D.  Temper  color  should  be  light 
yellow. 

The  tool  may  be  forged  by  starting  with  a  fuller 
cut,  as  shown  at  A,  Fig.  236.  The  blade  is  roughly 


i66 


FORGE-PRACTICE. 


forged  into  shape  with  a  sledge,  or,  on  light  stock, 
a  hand-hammer,  working  over  the  edge  of  the  anvil 
to  form  the  shoulder  in  the  manner  shown  at  B. 
This  leaves  the  end  bulged  out  and  in  rough  shape, 


FIG.  236. 

similar  to  C.  The  end  should  be  trimmed  off  with 
a  sharp  hot-chisel  along  the  dotted  line. 

The  finishing  may  be  done  over  the  corner  of  the 
anvil,  using  a  hand-hammer  or  flatter,  in  the  same 
way  as  when  starting  the  tool;  or  a  set -hammer 
may  be  used,  as  shown  at  D, 

Care  must  be  taken  to  have  proper  clearance  on 
all  sides  of  the  blade.  It  is  a  good  plan  to  upset 
the  end  of  the  blade  slightly  by  striking  a  few  light 
blows  the  last  thing  on  the  end  at  the  cutting 
edge,  then  ardding  a  little  clearance. 


TOOL    FORGING   AND    TEMPERING. 


I67 


When  a  tool  is  wanted  with  the  blade  forged  in 
the  center  of  the  shank,  the  two  shoulders  are 
formed  by  using  a  set-hammer  and  working  at  the 
edge  of  the  anvil  face,  letting  the  corner  of  the 
anvil  shape  one  shoulder  while  the  set-hammer  is 
forming  the  other.  This  process  has  been  de- 
scribed before  under  the  general  method  of  form- 
ing double  shoulders. 

Bent  Cutting-off  Tool. — The  bent  cutting-off  tool, 


I         \\ 


FIG.  237. 

Fig.  237,  is  made  and  tempered  exactly  the  same 
as  the  straight  tool,  excepting  that  the  blade  is 
bent  backward  toward  the  shank  through  an  angle 
of  about  45  degrees. 


FIG.  238. 

Boring  Tool. — The  boring  tool,  illustrated  in  Fig. 
238,  needs  no  particular  description.  The  length 
of  the  thin  shank  depends  upon  the  depth  of  the 


1 68  FORGE-PRACTICE. 

hole  the  tool  is  to  be  used  in,  but,  as  a  general 
rule,  should  not  be  made  any  longer  than  necessary. 

This  thin  shank  is  started  with  a  fuller  cut  and 
drawn  out  in  much  the  same  way  as  the  cutting-off 
tool  was  started. 

The  cutting  edge  is  at  the  end  of  the  small,  bent 
nose.  The  only  part  of  the  tool  required  tempered 
is  the  bent  nose,  or  end,  which  should  be  given  the 
same  temper  color  as  the  other  lathe-tools — light 
yellow. 

Internal  Thread  Tool. — This  tool,  used  for  cut- 
ting screw  threads  on  the  inside  of  a  hole,  is  forged 
to  the  same  shape  as  the  boring  tool  described 
above,  the  end  being  afterward  ground  somewhat 
differently. 

Diamond-points. — These  tools  are  made  right  and 
left. 


FIG.  239. 

There  are  several  good  methods  of  making  these 
tools;  but  the  one  given  below  is  about  as  quick 
and  easy  as  any,  and  requires  the  use  of  no  tools 
excepting  the  hand-hammer  and  sledge. 

The  diamond-point  is  started  as  shown  at  A ,  Fig. 
240,  by  holding  the  stock  at  an  angle  of  about  45 
degrees  over  the  outside  edge  of  the  anvil.  It  is 
first  slightly  nicked  by  being  driven  down  with  a 


TOOL   FORGING   AND   TEMPERING. 


169 


sledge  against  the  corner,  and  the  bent  end  down 
to  the  dotted  position  with  a  few  blows,  as  indi- 
cated by  the  arrow. 


FIG.  240. 


This  end  is  further  bent  by  holding  and  striking 
as  illustrated  at  B.  The  diamond  shape  is  given 
to  the  end  by  swinging  the  tool  back  and  forth  and 


170 


FORGE-PRACTICE. 


striking  as  shown  at  (7,  which  gives  a  side  and  end 
view  of  tool  in  position  on  the  anvil. 

The  tool  is  finished  by  trimming  the  end  with 
a  sharp  hot-chisel  and  so  bending  the  end  as  to 
throw  the  top  of  the  nose  slightly  to  one  side,  giv- 
ing the  necessary  side  ' 'rake"  as  shown  in  Fig.  239. 

When  hardening,  the  end  should  be  dipped  as 
shown  at  D  and  the  temper  drawn  to  show  light- 
yellow  scale. 

Tools  like  the  above  made  of  stock  as  large  as 
J"X  i"  may  be  made  using  the  hand-hammer  alone. 


FIG.  241. 

Side  Tools. — Side  tools,  or  side-finishing  tools,  as 
they  are  also  called,  are  generally  made  about  the 
shape  shown  in  Fig.  241.  These  tools  are  made 
right  and  left  and  are  also  made  bent.  The  bent 


TOOL  FORGING   AND    TEMPERING.  171 

side  tools  have  the  ends  forged  the  same;  but  the 
blade  is  afterward  bent  toward  the  shank,  cutting 
edge  out,  at  an  angle  of  about  45  degrees. 

The  side  tool  may  be  started  by  making  a  fuller 
cut  as  shown  at  A,  Fig.  241,  near  the  end  of  the 
stock. 

The  part  of  the  stock  marked  x  is  then  drawn 
out  by  using  a  fuller  turned  in  the  opposite  direc- 
tion, working  the  stock  down  into  the  shape  shown 
at  B.  The  blade  is  smoothed  up  with  a  set-ham- 
mer and  trimmed  with  a  hot-chisel  along  the  dotted 
lines  on  C.  The  curved  end  of  the  blade  is  smoothed 
up  and  finished  with  a  few  blows  of  the  hand-ham- 
mer. 

The  tool  is  finished  by  giving  the  proper  ' ' offset" 
to  the  top  edge  of  the  blade.  This  is  done  by  plac- 
ing the  tool,  flat-side  down,  with  the  blade  ex- 
tending over,  and  the  end  of  the  blade  next  the 
shank  about  one-eighth  of  an  inch  beyond,  the 
outside  edge  of  the  anvil.  A  set-hammer  is  placed 
on  the  blade  close  up  to  the  shoulder  and  slightly 
tipped,  so  that  the  face  of  the  hammer  touches  the 
thin  edge  of  the  blade  only,  as  illustrated  at  D. 
One  or  two  light  blows  with  the  sledge  will  give 
the  necessary  offset,  and  after  straightening  the 
blade  the  tool  is  ready  for  tempering. 

It  is  very  important  on  these  tools,  as  well  as  on 
all  others,  to  have  the  cutting  edge  as  smooth  and 
true  as  possible;  it  is,  therefore,  best,  the  very  last 
thing,  to  smooth  up  this  part  of  a  tool,  using  the 
hand-  or  set-hammer.  Above  all  things,  the  cut- 
ting edge  must  not  be  rounded  off,  as  this  necessi- 


172 


FORGE-PRACTICE. 


tates  grinding  down  the  edge  until  the  rounded 
part  has  been  completely  ground  off. 

While  the  side  tool  is  being  heated  for  temper- 
ing, it  should  be  placed  in  the  fire  with  the  cutting 
edge  up.  It  is  more  easy  to  avoid  overheating  of 
the  edge  in  this  way. 

The  blade  is  hardened  by  dipping  in  water  as 
shown  at  E,  only  a  small  part  of  back,  A,  of  the 
blade  extending  above  the  water  and  remaining 
red-hot.  The  tool  is  taken  from  the  water,  quickly 
polished  on  the  flat  side,  and  the  temper  drawn  to 
show  a  very  light  yellow.  The  same  color  should 
show  the  entire  length  of  the  cutting  edge.  If  the 
color  shows  darker  at  one  end,  it  indicates  that 
that  end  of  the  blade  was  not  cooled  enough,  and 
the  tool  should  be  rehardened,  this  time  tipping 
the  tool  in  such  a  way  as  to  bring  that  end  of  the 
blade  which  was  before  too  soft  deeper  in  the  water. 
Centering  Tool. — The  centering  tool,  Fig.  242, 
used  for  starting  holes  on  face-plate  and  chuck 

work,  is  started  in 
much  the  same  way 
as  the  boring  tool. 
The  end  is  flattened 
out  thin  and  trimmed 
into  shape  with  a  hot- 
chisel.  The  right- 

hand  side  of  the  end  should  be  cut  from  the  top  side 
and  the  left-hand  from  the  other,  leaving  the  end 
the  same  shape  as  a  flat  drill. 

Tempered  the  same  as  other  lathe-tools. 
Finishing  Tool. — This  tool,  Fig.  243,  is  started  by 


TOOL    FORGING    AND    TEMPERING. 


173 


bending  the  end  of  the  stock  down  over  the  edge  of 

the    anvil  in  the   same  way 

as  when  starting  the  diamond-      1 — i 

point. 

The  end  is  flattened  and 
widened  by  working  with  a 
hand-  or  set-hammer,  as  FlG-  243- 

shown  at  A,  Fig.  244.  This  leaves  the  end  bent 
out  too  nearly  straight;  but,  after  being  shaped,  it 
is  bent  into  the  proper  angle,  in  the  manner  illus- 


FIG.  244. 

trated  at  B.  The  blade  will  then  probably  be  bent 
somewhat  like  C,  but  a  few  blows  with  a  hammer,  at 
the  point  and  in  the  direction  indicated  by  the 
arrow,  will  straighten  this  out,  leaving  it  like  D. 
After  trimming  and  smoothing,  the  tool  is  ready 


1 74  FORGE  PRACTICE. 

for  tempering.  The  blade  should  be  tempered  to 
just  show  the  very  lightest  yellow  at  cutting  edge. 

When  a  tool  of  this  kind  is  to  be  used  on  a  planer, 
the  front  end  should  make  more  nearly  a  right  angle 
with  the  bottom;  or,  in  other  words,  there  should 
be  less  front  "rake"  or  "clearance." 

Flat  Drills.  — The  flat  drill,    Fig.   245,   needs  no 


FIG.  245. 

description,  as  the  forging  and  shaping  are  very 
simple.  The  end  should  be  trimmed  the  same  as 
the  centering  tool.  The  size  of  the  tool  is  deter- 
mined by  the  dimension  A,  this  being  the  same  size 
as  the  hole  the  drill  is  intended  to  make;  thus,  if 
this  dimension  were  i  n ',  the  drill  would  be  known 
as  an  inch  drill. 

The  temper  is  drawn  to  show  a  dark-yellow  scale. 

Hammers. — As  a  general  rule,  when  making  ham- 
mers of  all  kinds  by  hand  the  eye  is  made  first.  A 
bar  of  steel  of  the  proper  size  and  convenient  length 
for  handling  is  used,  and  the  hammer  forged  on 
the  end,  as  much  forging  and  shaping  as  possible 
being  done  before  cutting  the  hammer  from  the 
bar. 

The  hole  for  the  eye  is  punched  in  the  usual  way 
at  the  proper  distance  from  the  end  of  the  bar, 
using  a  punch  having  a  handle  (Fig.  70). 

The  nose  of  the  punch  is  slightly  smaller  but  has 
the  same  shape  as  the  eye  is  to  finish.  Great  care 


TOOL   FORGING   AND    TEMPERING.  175 

must  be  taken  to  have  the  hole  true  and  straight. 
It  is  very  difficult  and  sometimes  impossible  to 
straighten  up  a  crooked  hole. 

After  punching  the  eye,  the  sides  of  the  stock 
are  generally  bulged  out,  and  to  prevent  knock- 
ing the  eye  out  of  shape  while  forging  down  this 
bulge  a  drift-pin,  Fig.  246,  is  used.  This  is  made 


of  tool-steel  and  tapers  from  near  the  center  to- 
ward each  end,  one  end  being  somewhat  smaller 
than  the  other.  The  center  of  the  pin  is  the  same 
shape  and  size  as  the  eye  is  to  be  in  the  hammer. 

When  the  bar  has  been  heated  the  drift-pin  is 
driven  tightly  into  the  hole  and  the  bulge  forged 
down  in  the  same  way  (B,  Fig.  248)  as  a  solid  bar 
would  be  treated.  When  the  drift-pin  becomes 
heated  it  must  be  driven  out  and  cooled,  and  under 
no  circumstances  should  the  bar  be  heated  with 
the  pin  in  the  hole.  The  pin  should  always  be 
used  when  there  is  danger  of  knocking  the  eye  out 
of  shape. 

The  steel  used  for  hammers,  and  ' '  battering 
tools"  in  general,  should  be  of  a  lower  temper  (con- 
tain less  carbon)  than  that  used  for  lathe-tools. 

The  eye  of  a  hammer  should  not  be  of  uniform 
size  throughout,  but  should  be  larger  at  the  ends 


i76 


FORGE-PRACTICE. 


and  taper  slightly  toward  the  center,  as  illustrated 
in  Fig.  247,  which  shows  a  section  of  a  hammer  cut 
through  the  center  of  the  eye. 
When  the  eye  is  made  in  this 
way  (slightly  contracted  at 
the  middle),  the  hammer- 
handle  may  be  driven  in 


FIG.  247- 


tightly  from  one  end;  then  by  driving  one  or  more 
wedges  in  the  end  of  the  handle  it  is  held  firmly 
in  place  and  there  is  no  chance  for  the  head  to 
work  up  or  down. 

Cross-perie,   Blacksmith's  or   Riveting   Hammer. — A 
hammer  of  this  kind  is  shown  at  C,  Fig.  6. 


FIG.  248. 

The  different  steps  in  the  process  of  forging  are 
illustrated  in  Fig.  248.  First  the  eye  is  punched 
as  shown  at  A.  The  pene  is  then  drawn  out  and 


TOOL   FORGING   AND    TEMPERING.  177 

shaped  and  a  cut  started  at  the  point  where  the 
end  of  the  hammer  will  come  (C),  the  drift-pin 
being  used,  as  shown  at  B,  while  forging  the  metal 
around  the  eye. 

The  other  end  of  the.  hammer  is  then  worked  up 
into,  shape,  using  a  set -hammer  as  indicated  at  D. 

When  the  hammer  is  as  nearly  finished  as  may  be 
while  still  on  the  bar,  it  is  cut  off  with  a  hot-chisel, 
leaving  the  end  as  nearly  square  and  true  as  pos- 
sible. 

After  squaring  up  and  truing  the  face  the  ham- 
mer is  tempered. 

For  tempering,  the  whole  hammer  is  heated  in  a 
slow  fire  to  an  even  hardening  heat;  while  harden- 
ing, the  tongs  should  grasp  the  side  of  the  hammer, 
one  jaw  being  inserted  in  the  eye. 

Both  ends  should  be  tempered,  this  oeing  done 
by  hardening  first  one  end,  then  the  other. 

The  small  end  is  hardened  first  by  cooling,  as 
shown  in  Fig.  249.  As  soon  as  this  end  has  cooled, 
the  position  is  instantly 
reversed  and  the  large 
end  of  the  hammer  dipped 
in  the  water  and  hard- 
ened. While  the  large 
end  is  cooling,  the  smaller 
one  is  polished  and  the 
temper  color  watched  for. 
When  a  dark-brown  scale 
appears  at  the  end  the  FIG.  249. 

hammer  is  again  reversed,  bringing  the  large  end 
uppermost  and  the  pene  in  the  water.  The  face 


178  FORGE-PRACTICE. 

end  is  polished  and  tempered  in  the  same  way  as 
the  small  end.  If  the  large  end  is  properly  hard- 
ened before  the  temper  color  appears  on  the  small 
end,  the  hammer  may  be  taken  completely  out  of 
the  water  and  the  large  end  also  polished,  the 
colors  being  watched  for  on  both  ends  at  once.  As 
soon  as  one  end  shows  the  proper  color  it  is  promptly 
dipped  in  water,  the  other  end  following  as  soon  as 
the  color  appears  there. 

Under  no  circumstances  should  the  eye  be  cooled 
while  still  red-hot. 

For  some  special  work  hammer-faces  must  be 
very  hard;  but  for  ordinary  usage  the  temper  as 
given  above  is  very  satisfactory. 

Ball  Pene-hammer. — The  ball  pene-hammer,  Fig. 
5,  is  started  by  punching  the  eye. 

The  hammer  is  roughed  out  with  two  fullers  in 
the  manner  illustrated  at  A,  Fig.  250. 

The  size  of  stock  used  should  be  such  that  it  will 
easily  round  up  to  form  the  large  end  of  the  hammer. 

After  the  hammer  is  roughed  out  as  shown  at  A, 
the  metal  around  the  eye  is  spread  side  wise,  using 
two  fullers  as  illustrated  at  B,  a  set-hammer  being 
used  for  finishing.  This  leaves  the  forging  like  C. 
The  next  step  is  to  round  and  shape  the  ball,  which 
is  forged  as  nearly  as  possible  to  the  finished  shape. 

After  doing  this  a  cut  is  made  in  the  bar  where 
the  face  of  the  hammer  will  come,  and  the  large  end 
rounded  up,  leaving  the  work  like  D. 

The  necked  parts  of  the  hammer  each  side  of 
the  eye  are  smoothed  and  finished  with  fullers  of 
the  proper  size.  Some  hammers  are  made  with 


TOOL  FORGING  AND   TEMPERING. 


179 


these  necks  round  in  section,  but  the  commoner 
shape  is  octagonal. 

After  smoothing  off,  the  hammer  is  cut  from  the 
bar  and  the  face  forged  true.  Both  ends  are  ground 
true  and  tempered.  This  hammer  should  be  tem- 


FIG.  250. 

pered  in  the  same  way  as  described  above  for  tem- 
pering the  riveting-hammer. 

Ball  pene-hammers  may  be  made  with  the  steam- 
hammer  in  practically  the  same  way  as  described, 
only  substituting  round  bars  of  steel  for  use  in 
place  of  fullers. 

Sledges. — Sledges  are  made  and  tempered  in  the 
same  general  way  as  riveting -hammers.  Sledges 
may  be  forged  and  finished  almost  entirely  under 
the  steam-hammer. 


l8o  FORGE-PRACTICE. 

Blacksmith's  Cold-chisel.  —  This  tool  (Fig.  2)  is 
forged  in  practically  the  same  way  as  the  cross-pene 
hammer  described  before.  The  end,  of  course,  is 
drawn  out  longer  and  thinner,  the  thin  edge  com- 
ing parallel  with  the  eye  instead  of  at  right  angles 
to  it. 

The  cutting  edge  only  of  the  chisel  is  tempered. 
The  temper  should  be  drawn  to  show  a  bluish 
scale  just  tinged  with  a  little  purple.  Under  no 
circumstances  should  the  head  of  the  chisel  be 
hardened,  as  this  would  cause  the  end  to  chip 
when  in  use  and  might  cause  a  serious  accident. 

The  tool  shown  in  Fig.  192  may  be  used  to  ad- 
vantage when  making  hot-  or  cold-chisels  with  the 
steam-hammer.  By  using  this  tool,  as  illustrated 
in  Fig.  193,  the  blade  of  the  chisel  may  be  quickly 
drawn  out  and  finished. 

Hot-chisel.  —  After  forming  the  eye  of  the  hot- 
chisel  (Fig.  2),  the  blade  is  started  by  making  the 

two  fuller  cuts,  as  il- 
lustrated in  Fig.  251. 
The  end  is  drawn 
^/''  down  as  indicated  by 
the  dotted  lines.  The 
head  is  shaped  and 

the  chisel  cut  from  the  bar  in  the  same  way  that 
the  riveting-hammer  was  treated. 

This  chisel  should  have  its  cutting  edge  tem- 
pered the  same  as  that  of  the  cold-chisel. 

Hardies. — Hardies  such  as  shown  in  Fig.  2 
should  be  started  by  drawing  out  the  stem.  This 
stem  is  drawn  down  to  the  right  size  to  fit  the 


TOOL   FORGING   AND    TEMPERING.  jgl 

hardy-hole  in  the  anvil  and  the  piece  cut  from  the 
bar.  This  is  heated,  the  stem  placed  in  the  hole 
in  the  anvil,  and  the  piece  driven  down  into  the 
hole  and  against  the  face  of  the  anvil,  thus  forming 
a  good  shoulder  between  the  stem  and  the  head  of 
the  hardy. 

After  forming  the  shoulder,  the  blade  is  worked 
out,  starting  by  using  two  fullers  in  the  same  way 
as  w^hen  starting  the  hot-chisel  blade. 

The  cutting  edge  should  be  given  the  same  tem- 
per as  a  cold-chisel. 

Blacksmith's  Punches.  —  Punches  shaped  similar 
to  Fig.  70  are  started  the  same  manner  as  the  hot- 
chisel,  excepting  that 
the  fuller  cuts  are 
made  on  four  sides,  as 
shown  in  Fig.  252. 
The  end  is  then  drawn 
out  to  the  shape  FIG.  252. 

shown    by  the    dotted 
lines. 

Temper  same  as  cold-chisel. 

Set-hammers  —  Flatters.  —  The  set-hammer,  Fig. 
15,  is  so  simple  that  no  directions  are  necessary  for 
shaping.  The  face  only  should  be  tempered  and 
that  should  show  a  dark-brown  or  purple  color. 

Flatters  such  as  shown  in  Fig.  14  may  be  made 
by  upsetting  the  end  of  a  small  bar,  the  upset  part 
forming  the  wide  face;  or  a  bar  large  enough  to 
form  the  face  may  be  used  and  the  head,  or  shank, 
drawn  down. 

The  eye  should  be  punched  after  the  face  has  been 


182 


FORGE -PRACTICE. 


FIG.  253. 


made.     The  face  should  be  tempered  to  about  a 

blue. 

When  many  are  to  be 
made  a  swage  -  block 
similar  to  Fig.  253 
should  be  used.  Half 
only  of  the  block  is 
shown  in  the  figure,  the 
other  half  being  cut  away 
to  show  the  shape  of  the 

hole  which  is  the  size  of  the  finished  flatter. 

When  using  this  block  the  stock  is  first  cut  to 

the  proper  length,  heated,  placed  in  the  hole,  and 

upset. 

Swages. — Swages  may    also  be  made  in  a  block 

similar  to  the  one  used  for  the  flatter.     The  swage 

should  be  first  upset  in  the  block  and  the  crease 

formed  the  last  thing.     The  crease  may  be  made 

with  a  fuller  or  a  bar  of  round  stock  the  proper 

size. 

Fullers. — -Fullers  are  made  in  the  same  way  as 

swages. 

All  of  these  tools  may  be  upset  and  forged  under 

the  steam-hammer,  using  the  die,  or  swage,  blocks 

as   described   above.      The   swage-blocks  may   be 

made  of  cast  iron. 


CHAPTER  X. 

MISCELLANEOUS  WORK. 

Shrinking. — When  iron  is  heated  it  expands,  and 
upon  being  cooled  it  contracts  to  practically  its 
original  size. 

This  property  is  utilized  in  doing  what  is  known 
as  "shrinking." 


FIG.  254. 

A  common  example  of  this  sort  of  work  is  illus- 
trated in  Fig.  254,  showing  a  collar  "shrunk"  on  a 
shaft.  The  collar  and  shaft  are  made  separately. 
The  inside  diameter  of  the  hole  through  the  collar 
is  made  slightly  less  than  the  outside  diameter  of 
the  shaft.  When  the  collar  and  shaft  are  ready 
to  go  together  the  collar  is  heated  red-hot.  The 
high  temperature  causes  the  metal  to  expand  and 
thus  increases  the  diameter  of  the  hole,  making 
it  larger  (if  the  sizes  have  been  properly  propor- 
tioned) than  the  outside  diameter  of  the  shaft. 
The  collar  is  then  taken  from  the  fire,  brushed 
clean  of  all  ashes  and  dirt,  and  slipped  on  the  shaft 

183 


I&J.  FORGE-PRACTICE. 

and  into  the  proper  position,  where  it  is  cooled  as 
quickly  as  possible.  This  cooling  causes  the  collar 
to  contract  and  locks  it  firmly  in  place. 

If  the  collar  be  al'owed  to  cool  slowly  it  will  heat 
the  shaft,  which  will  expand  and  stretch  the  collar 
somewhat;  then,  as  both  cool  together  and  con- 
tract, the  collar  will  be  loose  on  the  shaft. 

This  is  the  method  used  for  shrinking  tires  on 
wheels.  The  tire  is  made  just  large  enough  to  slip 
on  the  wheel  when  hot,  but  not  large  enough  to  go 
on  cold.  It  is  then  heated,  put  in  place,  and 
quickly  cooled. 

Couplings  are  frequently  shrunk  on  shafts  in  this 
way. 

Brazing. — Brazing,  it  might  be  said,  is  soldering 
with  brass. 

Briefly  the  process  is  as  follows :  The  surfaces  to 
be  joined  are  cleaned  thoroughly  where  they  are  to 
come  in  contact  with  each  other.  The  pieces  are 
then  fastened  together  in  the  proper  shape  by 
binding  with  wire,  or  holding  with  some  sort 
of  clamp.  The  joint  is  heated,  a  flux  (gener- 
ally borax)  being  added  to  prevent  oxidation  of 
the  surfaces,  and  the  "spelter"  (prepared  brass) 
sprinkled  over  the  joint,  the  heat  being  raised  until 
the  brass  melts  and  flows  into  the  joint,  making  a 
union  between  the  pieces.  Ordinarily  it  requires  a 
bright-red  or  dull-yellow  heat  to  melt  the  brass 
properly. 

Almost  any  metal  that  will  stand  the  heat  can  be 
brazed.  Great  care  must  be  used  when  brazing 
cast  iron  to  have  the  surfaces  in  contact  properly 


MISCELLANEOUS    WORK. 


185 


cleaned  to  start  with,  and  then  properly  protected 
from  the  oxidizing  influences  of-  the  air  and  fire 
while  being  heated. 

Brass  wire,  brass  filings,  or  small  strips  of  rolled 
brass  may  be  used  in  place  of  the  spelter.  Brass 
wire  in  particular  is  very  convenient  to  use  in  some 
places,  as  it  can  be  bent  into  shape  and  held  in  place 
easily. 

A  simple  brazed  joint  is  illustrated  in  Fig.  255, 
which  shows  a  flange  (in  this  case  a  large  washer) 
brazed  around  the  end  of  a  pipe.  It  is  not  neces- 
sary to  use  any  clamps  or  wires  to  hold  the  work 
together,  as  the  joint  may  be  made  tight  enough  to 
hold  the  pieces  in  place.  The  joint  should  be  tight 
enough  in  spots  to  hold  the  pieces  together,  but 
must  be  open  enough  to  allow  the  melted  brass  to 
run  between  the  two  pieces.  Where  the  pipe 
comes  in  contact  with  the  flange  the  outside  should 
be  free  from  scale  and  filed  bright,  the  inside  of 
the  flange  being  treated  in  the  same  way. 


-t 


BRASS 
'WIRE 


FIG.  255.  FIG.  256. 

When  the  pieces  have  been  properly  cleaned  and 
forced  together,  a  piece  of  brass  wire  should  be 
bent  around  the  pipe  at  the  joint,  as  shown  in  Fig. 
256,  and  the  work  laid  on  the  fire  with  the  flange 


jg6  FORGE-PRACTICE. 

down.  The  fire  should  be  a  clean  bright  bed  of 
coals.  As  soon  as  the  work  is  in  the  fire  the  joint 
should  be  sprinkled  with  the  flux;  in  fact,  it  is  a 
good  plan  to  put  on  some  of  the  flux  before  putting 
the  work  in  the  fire.  Ordinary  borax  can  be  used 
as  a  flux,  although  a  mixture  of  about  three  parts 
borax  and  one  part  sal  ammoniac  seems  to  give 
much  better  results. 

The  heat  should  be  gradually  raised  until  the 
brass  melts  and  runs  all  around  and  into  the  joint, 
when  the  piece  should  be  lifted  from  the  fire. 

The  brazing  could  be  done  with  spelter  in  place 
of  the  brass  wire.  If  spelter  were  to  be  used  the 
piece  would  be  laid  on  the  fire  and  the  joint  cov- 
ered with  the  flux  as  before.  As  soon  as  the  flux 
starts  to  melt,  the  spelter  mixed  with  a  large 
amount  of  flux  is  spread  on  the  joint  and  melted 
down  as  the  brass  wire  was  before.  For  placing 
the  spelter  when  brazing  it  is  convenient  to  have  a 
sort  of  a  long-handled  spoon.  This  is  easily  made 
by  taking  a  strip  of  iron  about  £"  X  J"  three  or  four 
feet  long  and  hollowing  one  end  slightly  with  the 
pene  end  of  the  hammer. 

There  are  several  grades  of  spelter  which  melt  at 
different  heats.  Soft  spelter  melts  at  a  lower  heat  than 
hard  spelter,  but  does  not  make  as  strong  a  joint. 

Spelter  is  simply  brass  prepared  for  brazing  in 
small  flakes  and  can  be  bought  ready  for  use.  The 
following  way  has  been  recommended  for  the  prep- 
aration of  spelter:  Soft  brass  is  melted  in  a  ladle 
and  poured  into  a  bucket  filled  with  water  having 
in  it  finely  chopped  straw,  the  water  being  given  a 


MISCELLANEOUS   WORK. 


I87 


swirling  motion  before  pouring  in  the  brass.  The 
brass  settles  to  the  bottom  in  small  particles.  Care 
must  be  taken  when  melting  the  brass  not  to  burn 
out  the  zinc.  To  avoid  this,  cover  the  metal  in 
ladle  with  powdered  charcoal  or  coal.  When  the 
zinc  begins  to  burn  it  gives  a  brilliant  flame  and 
dense  white  smoke,  leaving  a  deposit  of  white  oxide 
of  zinc. 

Another  example  of  brazing  is  the  T  shown  in 


FIG.  257. 

'ig.  257.     Here  two  pipes  are  to  be  brazed  to  each 
other  in  the  form  of  an  inverted  T. 

A  clamp  must  be  used  to  hold  the  pieces  in  proper 
position  while  brazing,  as  one  pipe  is  simply  stuck 
on  the  outside  of  the 
other.  A  simple 
clamp  is  shown  in  Fig. 
258  consisting  of  a 
piece  of  flat  iron  hav- 
ing one  hole  near  each 
end  to  receive  the  two 
small  bolts,  as  illus- 
trated. This  strip  lies 


FIG.  258. 


across  the  end  of  the 
pipe  forming  the  short 
stem  of  the  T,  and  the  bent  ends  of  the  bolts  hook 


1 88  FORGE-PRACTICE. 

into  the  ends  of  the  bottom  pipe.  The  whole  is  held 
together  by  tightening  down  on  the  nuts. 

The  brazing  needs  no  particular  description,  as 
the  spelter  or  wire  is  laid  on  the  joint  and  melted 
into  place  as  before. 

A  piece  of  this  kind  serves  as  a  good  illustration  of 
the  strength  of  a  brazed  joint.  If  a  well-made 
joint  of  this  kind  be  hammered  apart,  the  short 
limb  will  sometimes  tear  out  or  pull  off  a  section  of 
the  longer  pipe,  showing  the  braze  to  be  almost  as 
strong  as  the  pipe. 

When  using  borax  as  a  flux  the  melted  scale 
should  be  cleared  (or  scraped)  from  the  work  while 
still  red-hot,  as  the  borax  when  cold  makes  a  hard, 
glassy  scale  which  can  hardly  be  touched  with  a 
file.  The  cleaning  may  be  easily  done  by  plunging 
the  brazed  piece,  while  still  red-hot,  into  water. 
On  small  work  the  cleaning  is  very  thoroughly  done 
if  the  piece,  while  still  red-hot,  is  dipped  into  melted 
cyanide  of  potassium  and  then  instantly  plunged 
into  water.  If  allowed  to  remain  in  the  cyanide 
many  seconds  the  brass  will  be  eaten  off  and  the 
brazing  destroyed. 

It  is  not  always  necessary  when  brazing  wrought 
iron  or  steel  to  have  the  joint  thoroughly  cleaned; 
for  careful  work  the  parts  to  be  brazed  together 
should  be  bright  and  clean,  but  for  rough  work  the 
pieces  are  sometimes  brazed  without  any  preparation 
whatever  other  than  scraping  off  any  loose  dirt  or  scale. 

Pipe-bending.  —  There  is  one  simple  fact  about 
pipe-bending  which,  if  always  carried  in  mind, 
makes  it  comparatively  easy. 


MISCELLANEOUS    WORK. 


i89 


Let  the  full  lines  in  Fig.  259  represent  a  cross- 
section  of  a  piece  of  pipe  before  bending.  Now 
suppose  the  pipe  be  heated  and  an  attempt  made 
to  bend  it  without  taking  any  precautions  what- 


FIG.  259. 


260. 


ever.  The  concave  side  of  the  pipe  will  flatten 
down  against  the  outside  of  the  curve,  leaving  the 
cross-section  something  as  shown  by  the  dotted 
lines;  that  is,  the  top  and  bottom  of  the  pipe  will 
be  forced  together,  while  the  sides  will  be  pushed 
apart.  In  other  words,  the  pipe  collapses. 

If  the  sides  can  be  prevented  from  bulging  out 
while  being  bent  it  will  stop  the  flattening  together 
of  the  top  and  bottom.  A  simple  way  of  doing 
this  is  to  bend  the  pipe  between  two  flat  plates  held 
the  same  distance  apart  as  the  outside  diameter  of 
the  pipe  (Fig.  260).  Pipe  can  sometimes  be  bent 
in  a  vise  in  this  way,  the  jaws  of  the  vise  taking 
the  place  of  the  flat  plates  mentioned  above. 

Large  pipe  may  be  bent  something  in  the  follow- 
ing way:  If  the  pipe  is  long  and  heavy  the  part  to 
be  bent  should  be  heated,  and  then  while  one  end  is 


FORGE-PRACTICE. 


supported,  the  other  end  is  dropped  repeatedly  on 
the  floor.  The  weight  of  the  pipe  will  cause  it  to 
bend  in  the  heated  part.  Fig.  261  illustrates  this, 


FIG.  261. 

the  solid  lines  showing  the  pipe  as  it  is  held  before 
dropping  and  the  dotted  lines  the  shape  it  takes  as 
it  is  dropped. 

As  the  pipe  bends  the  sides,  of  course,  bulge  out, 
and  the  top  and  bottom  tend  to  flatten  together; 
but  this  is  remedied  by  laying  the  pipe  flat  and 
driving  the  bulging  sides  together  with  a  flatter. 

Another  way  of  bending  is  to  put  the  end  of  the 
pipe  in  one  of  the  holes  of  a  heavy  swage-block  (as 
illustrated  in  Fig.  262),  the  bend  then  being  made 


FIG.  262. 

by  pulling  over  the  free  end.  The  same  precau- 
tion must,  of  course,  be  taken  as  when  bending  in 
other  ways. 

The  fact  that  by  preventing  the  sides  of  the  pipe 
from  bulging  it  may  be  made  to  retain  its  proper 


MISCELLANEOUS    WORK. 


IQI 


shape  is  particularly  valuable  when  several  pieces 
are  to  be  bent  just  alike.  In  this  case  a  jig  is  made 
which  consists  of  two  side  plates,  to  prevent  the 
sides  of  the  pipe  from  bulging,  and  a  block  between 
these  plates  to  give  the  proper  shape  to  the  curve. 
A  piece  of  bent  pipe  which  was  formed  in  this 


FIG.  263. 

way  is  shown  in  Fig.  263,  together  with  the  jig 
used  for  bending  it. 

The  pipe  was  regular  one-quarter-inch  gas-pipe. 
The  jig  was  made  as  follows:  The  sides  were  made 
of  two  pieces  of  board  about  ij"  thick.  Between 
these  sides  was  a  board,  A,  sawed  to  the  shape  of 
the  inside  curve  of  the  bent  pipe.  This  piece  was 
slightly  thicker  than  the  outside  diameter  of  the 
pipe  (about  Y32"  being  added  for  clearance).  The 
inside  face  of  the  sides  and  the  edge  of  the  block  A 
were  protected  from  the  red-hot  pipe  by  a  thin 
sheet  of  iron  tacked  to  them. 

A  bending  lever  was  made  by  bending  a  piece  of 
i"Xi"  stock  into  the  shape  of  the  outside  of  the 
pipe.  This  lever  was  held  in  place  by  a  \"  bolt 
passing  through  the  sides  of  the  jig,  as  shown. 


1 92  FORGE-PRACTICE. 

To  bend  the  pipe  it  was  heated  to  a  yellow  heat, 
put  in  the  jig  as  indicated  by  the  dotted  lines  and 
the  lever  pulled  over,  forcing  the  hot  pipe  to  take 
the  form  of  the  block. 

A  jig  of  this  sort  is  easily  and  cheaply  made  and 
gives  good  service,  although  it  is  necessary  some- 
times to  throw  a  little  water  on  the  sides  to  prevent 
them  from  burning. 

Another  common  way  of  bending  is  to  fill  the 
pipe  with  sand.  One  end  of  the  pipe  to  be  bent  is 
plugged  either  with  a  cap  or  a  wooden  plug  driven 
in  tightly.  The  pipe  is  filled  full  of  sand  and  the 
other  end  closed  up  tight.  The  pipe  may  then  be 
heated  and  bent  into  shape.  It  is  necessary  to  have 
the  pipe  full  of  sand  or  it  will  do  very  little  good. 

For  very  thin  pipe  the  best  thing  is  to  fill  with 
melted  rosin.  This,  of  course,  can  only  be  used 
when  the  tubing  or  pipe  is  very  thin  and  is  bent 
cold,  as  heating  the  pipe  would  cause  the  rosin  to 
run  out. 

Thin  copper  tubing  may  be  bent  in  this  way. 

A  quite  common  form  of  pipe-bending  jig  is 
illustrated  in  Fig.  264. 

The  outside  edge  of  the  semicircular  casting  has 
a  groove  in  it  that  just  fits  half-way  round  the  pipe. 
The  small  wheel  attached  to  the  lever  has  a  cor- 
responding groove  on  its  edge.  When  the  two  are 
in  the  position  shown  the  hole  left  between  them 
is  the  same  shape  and  size  as  the  cross-section  of 
the  pipe. 

To  bend  the  pipe,  the  lever  is  swung  to  the  ex- 
treme left,  the  end  of  the  heated  pipe  inserted  in 


MISCELLANEOUS    WORK. 


193 


the  catch  at  A  (which  has  a  hole  in  it  the  same  size 
as  the  pipe),  and  the  lever  pulled  back  to  the  right, 
bending  the  pipe  as  it  goes. 

The  stem  on  the  lower  edge  of  the  casting  was 


FIG.  264. 

made  to  fit  in  a  vise,  where  the  jig  was  held  while 
in  operation. 

Annealing  Copper  and  Brass.  —  Brass  or  copper 
may  be  softened  or  annealed  by  heating  the  metal 
to  a  red  heat  and  cooling  suddenly  in  cold  water, 
copper  being  annealed  in  the  same  way  that  steel  is 
hardened.  Copper  annealed  this  way  is  left  very 
soft,  somewhat  like  lead.  Hammering  copper  or 
brass  causes  it  to  harden  and  become  springy. 
When  working  brass  or  copper,  if  much  bending  or 
hammering  is  done,  the  metal  should  be  annealed 
frequently. 


194  FORGE-PRACTICE. 

Bending  Cast  Iron. — It  is  sometimes  necessary  to 
straighten  castings  which  have  become  warped  or 
twisted.  This  may  be  done  to  some  extent  by 
heating  the  iron  and  bending  into  the  desired  shape. 
The  part  to  be  bent  should  be  heated  to  what  might 
be  described  as  a  dull-yellow  heat.  The  bending  is 
done  by  gradually  applying  pressure,  not  by  blows. 
For  light  work  two  pairs  of  tongs  should  give  about 
the  right  amount  of  leverage  for  twisting  and  bend- 
ing. 

When  properly  handled  (very  "gingerly"),  thin 
castings  may  be  bent  to  a  considerable  extent. 
Before  attempting  any  critical  work  some  experi- 
menting should  be  done  on  a  piece  of  scrap  to  deter- 
mine at  just  what  heat  the  iron  will  work  to  the 
best  advantage,  and  how  much  bending  it  will 
stand  without  breaking. 


HEAT   TREATMENT    OF    STEEL. 

This  important  subject  is  receiving  a  great  deal  of 
attention  in  all  up-to-date  manufacturing  plants 
whose  output  receives,  when  in  use,  any  unusual 
strains  demanding  conditions  that  are  not  manifest 
in  steel  treated  by  ordinary  methods.  The  subject 
covers  the  processes  of  heating  for  forging,  annealing, 
hardening  and  tempering  and  various  modifications 
of  the  processes  mentioned. 

The  most  important  factor  is  the  man  that  does  the 
work,  or  who  supervises  it.  Many  claims  are  made 
by  men  selling  furnaces,  heat-recording  instruments 
and  the  various  paraphernalia  used  in  a  heat-treating 


MISCELLANEOUS   WORK.  1 95 

plant  as  to  the  possibilities  to  be  obtained  when 
using  the  articles  they  sell.  Many  of  these  are  desir- 
able, some  are  indispensable.  But  best  results  can- 
not be  obtained  unless  they  are  used  by  a  "good" 
man.  There  is  no  furnace,  pyrometer  or  other  part 
of  the  equipment  of  a  heat-treating  plant  made  that 
will  take  the  place  of  brains.  In  fact,  the  better  the 
equipment,  the  better  the  man  needed  in  order  to  get 
maximum  results. 

To  obtain  best  results  when  heat-treating  steel  the 
workman  must  understand  the  metal  he  is  working 
on.  There  is  no  valid  excuse  at  the  present  time  for 
a  man  engaged  in  any  of  the  processes  of  heat- 
treating  steel  not  having  a  working  knowledge  of  the 
subject.  He  should  know  how  it  is  made,  what  ele- 
ments go  into  its  composition,  what  effect  each  of 
these  has  upon  the  steel,  the  effect  of  varying  per- 
centages, and  how  the  presence  of  certain  elements 
may  modify  the  effect  of  others.  The  effect  of  vari- 
ous temperatures  on  steel  of  different  analyses  and 
the  effect  of  cooling  heated  steel  at  different  time 
rates  should  be  understood.  While  a  long  experi- 
ence in  this  particular  line  of  business  is  a  valuable 
asset  to  any  man,  it  does  not  enable  him  to  suc- 
cessfully handle  tools  ancj  steels  that  he  is  not  famil- 
iar with. 

Twenty-five  years  ago  there  was  comparatively 
little  literature  devoted  to  this  subject.  To-day 
there  are  many  excellent  books  to  be  had.  Some  are 
of  particular  value  to  the  graduate  metallurgist  but 
of  little  use  to  the  practical  man  of  ordinary  educa- 
tion, others  are  so  written  that  they  are  of  value  to 


196  FORGE-PRACTICE. 

both,  while  still  others  are  intended  for  the  man 
who  is  devoting  his  time  to  the  actual  processes  in- 
volved in  the  practical  operations  in  the  heat- 
treating  room. 

The  workman  should  not  be  content  with  the 
study  of  the  latter  alone  as  he  will  never  understand 
the  subject  as  he  should  until  he  knows  the  metal  he 
is  treating.  Space  prevents  our  taking  up  the  study 
of  the  making  of  steel,  or  to  any  great  extent  the 
influence  of  the  elements,  but  the  writer  wishes  to 
urge  on  every  reader,  and  on  every  man  engaged 
in  heat-treating  steel  the  necessity  of  a  thorough 
study  of  steel  in  order  that  he  may  know  how  to  best 
apply  the  information  given  in  this,  and  other  books 
written  especially  for  the  practical  man. 

Steel  is  affected  by  heat  to  a  greater  degree  than  is 
generally  understood  Reference  to  any  one  of  a 
number  of  handbooks  will  convince  one  of  the  truth- 
fulness of  this  statement.  In  the  table  of  "Co- 
efficients of  the  Expansion  of  Solids"  is  found  the 
amount  steel  expands  per  degree  of  heat  absorbed. 
Reason  dictates  that  if  the  metal  is  expanded  by 
heat  the  various  portions  should  be  heated  as  uni- 
formly as  possible  in  order  that  uneven  expansion 
does  not  take  place,  because  if  one  portion  is  heated 
more  than  another  strains  are  set  up.  These  strains 
tend  to  weaken  or  rupture  the  steel.  If  these  strains  do 
not  manifest  themselves  at  the  time  the  piece  is  un- 
evenly heated  they  will  during  subsequent  treatment. 

While  it  is  necessary  to  uniformly  heat  steel  to 
avoid  the  trouble  just  mentioned,  long  exposure  of 
the  metal  to  high  heats,  especially  if  it  contains  con- 


MISCELLANEOUS   WORK.  IQ7 

siderable  carbon  tends  to  weaken  it.  Knowledge 
gained  by  experience  enables  the  operator  to  so  apply 
heat  that  the  desired  uniform  temperature  may  be 
obtained  with  the  minimum  of  weakness  due  to 
either  strains  or  long  heats. 

Steel  that  has  been  heated  for  forging,  annealing, 
hardening  or  any  of  the  other  processes  involved  in 
heat  treating  must  be  cooled.  The  method  and 
rapidity  of  cooling  has  a  pronounced  effect  on  the 
metal.  The  writer's  attention  was  called  to  a  batch 
of  forgings  that  could  not  be  machined  on  account 
of  hardness.  Investigation  showed  that  previous 
batches  which  had  machined  easily  had  been  placed 
in  an  iron  box,  in  the  bottom  of  which  was  a  quantity 
of  hot  ashes.  These  forgings  were  placed  in  the  box 
while  red  hot.  The  repeated  addition  of  forgings  as 
they  left  the  drop  hammer  prevented  rapid  cooling, 
thus  insuring  a  condition  that  made  machining  an 
easy  matter.  This  box  was  so  located  that  no  mois- 
ture or  drafts  of  air  could  reach  it.  The  forgings 
under  consideration  were  made  from  steel  of  the 
same  analysis  as  former  batches,  but  the  work  was 
done  by  a  "new  man"  and  thrown  while  red  hot 
onto  a  floor  of  damp  earth,  with  the  result  that  por- 
tions of  many  of  the  pieces  were  partially  hardened, 
thus  rendering  machining  impossible  until  they  were 
annealed.  The  cost  of  annealing,  plus  that  of  milling 
cutters  spoiled  in  the  attempt  to  machine  the  pieces, 
made  the  cost  of  that  particular  lot  greatly  in  excess 
of  what  it  should  have  been. 

In  some  lines  of  work,  especially  that  branch 
devoted  to  the  making  of  guns  of  certain  types,  and 


198  FORGE-PRACTICE. 

munitions,  certain  portions  of  the  product  are  given 
a  degree  of  hardness  before  the  finish  machining 
operations.  While  it  is  common  practice  in  many 
shops  to  harden  pieces  before  finishing  and  then 
bring  them  to  size  by  grinding  the  operations  referred 
to  above  are  accomplished  by  means  of  cutting  tools. 
This  practice  makes  necessary  a  very  exact  knowl- 
edge of  the  desirable  methods  of  treating  both  the 
product  and  the  cutting  tools  used.  Exact  tempera- 
tures and  time  exposures  to  heat  are  essential,  and 
as  these  vary  somewhat  according  to  the  composi- 
tion of  the  steel  used  intelligently  conducted  experi- 
ments aided  by  accurate  heat  determining  instru- 
ments are  necessary. 

Annealing,  while  primarily  a  softening  process, 
has  been  extended  so  as  to  produce  certain  desirable 
qualities  not  possessed  by  the  steel  as  furnished  by 
the  mills. 

Forgings  and  other  articles  are  many  times 
strengthened  and  toughened  to  a  degree  not  dreamed 
of  by  anyone  twenty-five  or  thirty  years  ago. 
These  results  are  directly  traceable  to  the  efforts  of 
men  who  are  thoroughly  familiar  with  the  nature 
and  composition  of  steel  and  the  effects  of  heat  on 
its  structure  and  strength.  The  credit  for  much  of 
this  knowledge  belongs  to  some  of  our  leading 
metallurgists  coupled  with  the'efforts  of  practical  men. 

While  a  technical  education  specialized  along  the 
lines  under  consideration  is  highly  desirable,  any 
man  of  ordinary  education  and  intelligence  can  by 
diligent  study  and  practice  acquire  a  knowledge  of 
the  subject  of  Steel  and  Its  Heat  Treatment  that 


MISCELLANEOUS   WORK.  199 

will  be  of  inestimable  value  to  himself  and  others. 
The  day  has  passed  when  some  one  man  who  was 
supposed  to  "know  it  all,"  or  who  by  the  applica- 
tion of  some  secret  powder,  or  other  concoction 
could  do  the  supposedly  impossible,  and  who,  as  a 
result,  could  dictate  the  running  of  this  branch  of 
the  business.  There  is  a  reason  for  everything,  and 
when  one  knows  the  reason  he  is  able  to  meet  almost 
any  emergency. 

Steel. — The  word  "steel"  conveys  very  little 
meaning  to  the  man  who  is  familiar  with  the  compo- 
sition of  the  various  alloys  of  iron  usually  grouped 
under  this  heading.  We  often  hear  the  terms  open- 
hearth  steel,  Bessemer  steel,  crucible  steel,  high  steel, 
low  steel,  hard  steel,  soft  steel,  alloy  steel,  etc.  A 
term  often  used  and  which  means  very  little  is 
machine  steel,  or  machinery  steel  as  it  is  sometimes 
called.  The  so-called  machine  steel  may  contain 
very  little  carbon,  or  it  may  have  a  fairly  high  per- 
centage. In  the  first  case  it  would  be  soft  and  com- 
paratively weak,  while,  in  the  latter,  it  would  be 
much  harder  and  stronger  under  a  steadily  applied 
load.  Under  ordinary  circumstances  both  would  be 
tagged  "machine  steel"  whether  made  by  either  the 
Bessemer  or  the  open-hearth  process,  provided  it  was 
to  be  used  in  making  parts  of  machines,  implements, 
etc. 

An  intelligent  study  of  the  subject  will  show  that 
steels  of  various  compositions  are  made  to  meet 
varying  demands.  In  ordinary  steels  the  element 
present  to  give  strength,  or  to  make  hardening  of 
the  metal  possible,  is  carbon,  and  as  this  element  is 


200  FORGE-PRACTICE. 

used  to  give  the  desired  condition  men  familiar  with 
the  metal  usually  distinguish  it  by  the  carbon  con- 
tent. The  term  "percentage  of  carbon"  is  used  by 
many  while  others  state  the  amount  in  "points." 
A  point  is  one  one-hundredth  part  of  one  per  cent  of 
any  element  that  goes  into  the  composition  of  iron 
or  steel.  A  4o-point  carbon  steel  contains  0.40  per 
cent  carbon.  In  speaking  of  this  steel  one  would 
say  4o-point  carbon  steel,  or  TO  per  cent  carbon  steel. 
If  it  was  made  by  the  open-hearth  process  it  would 
be  spoken  of  as  4o-point,  or  TV  per  cent,  open-hearth 
steel;  if  made  by  the  Bessemer  process  it  would 
be  called  4o-point,  or  T%  per  cent,  Bessemer  steel. 

The  product  of  the  Bessemer  converter  and  of  the 
open-hearth  furnace  having  the  same  carbon  con- 
tent may  be  similar  in  most  respects,  or  they  may  be 
widely  different.  As  the  time  consumed  in  running 
a  charge  in  the  converter  is  much  less  than  the  neces- 
sary time  in  the  open-hearth  furnace  the  product  is 
more  liable  to  be  variable. 

There  are  two  types  of  Bessemer  converters  and 
the  same  number  of  open-hearth  furnaces,  namely  the 
acid  and  basic,  and  the  product  of  each  is  known  as 
acid  steel  or  basic  steel.  Very  little,  if  any  basic 
Bessemer  steel  is  made  in  the  United  States,  while 
both  acid  and  basic  open-hearth  steels  are  produced 
here.  Knowing  these  facts  one  is  able  to  designate 
a  steel  very  accurately  by  stating  the  kind  and  car- 
bon content;  as,  6o-point  carbon  basic  open -hearth 
steel.  Under  ordinary  conditions  the  percentages 
of  other  elements  entering  into  the  composition  con- 
form very  nearly  to  fixed  formulas,  but  where  any  of 


MISCELLANEOUS  WORK.  2OI 

these  vary  to  any  degree  in  order  to  produce  some 
desired  result,  the  content  of  these  elements  is  stated 
also. 

The  custom  prevailing  in  some  shops  of  ordering 
so  many  feet  of  machine  steel  is  to  be  discouraged, 
for,  while  this  term  may  have  some  specific  meaning 
with  the  steel  manufacturer,  it  has  little  or  none 
with  the  average  mechanic,  purchasing  agent,  manu- 
facturer or  man  employed  in  a  steel  warehouse. 
The  receiving  of  stock  ordered  in  this  way  and  then 
of  storing  it  in  a  common  rack  has  been,  and  is  a 
source  of  unsatisfactory  product  and  serious  loss  to 
many  concerns. 

As  few  kinds  and  grades  of  steel  as  is  consistent 
with  good  results  should  be  used  in  any  one  plant 
unless  those  in  charge  have  a  working  knowledge  of 
steel,  and  closely  follow  the  various  kinds  and  grades, 
and  see  that  they  are  marked  or  tagged  so  they  can 
be  readily  distinguished,  as  otherwise  endless  con- 
fusion will  result. 

The  purchase  of  Bessemer  steel  for  any  purpose 
where  a  uniform  analysis  is  necessary,  or  where  it  is 
to  be  hardened  or  case  hardened  is  not  to  be  recom- 
mended unless  all  stock  received  is  to  be  subjected 
to  chemical  analysis  and  physical  tests.  Even  when 
these  precautions  are  observed  the  various  bars  in  a 
shipment  are  liable  to  vary  in  analysis  to  an  exten'c 
that  will  cause  serious  trouble.  For  this  reason  the 
use  of  trhe  product  of  the  acid  Bessemer  converter 
is  to  be  discouraged  where  the  product  is  to  be  hard- 
ened or  where  it  is  to  be  subjected  to  shock  or  inter- 
mittent strains  of  any  sort. 


202  FORGE-PRACTICE. 

If  acid  open-hearth  steel  is  to  be  case  hardened, 
and  especially  if  the  carburizer  to  be  used  is  raw 
bone,  the  phosphorus  content  in  the  steel  should  be 
low  as  the  effect  of  phosphorus,  if  present  in  more 
than  allowable  percentages,  is  to  produce  brittleness 
under  any  but  a  steady  load.  For  the  reasons  men- 
tioned it  is  generally  safer  to  use  basic  open-hearth 
steel  where  the  product  is  to  be  hardened  in  any  way. 
These  statements  are  intended  to  apply  to  plants 
whose  size  do  not  warrant  the  employing  of  a  chem- 
ist, and  where  the  purchaser  must  rely  on  the  steel 
warehouse  for  its  product. 

Most  steel  mills  will,  on  request,  give  an  analysis 
best  suited  to  a  given  purpose,  if  a  description  of  the 
work  to  be  made  together  with  the  physical  strains 
it  is  to  receive  in  use  are  stated. 

Alloy  Steels. — In  order  to  obtain  the  maximum  of 
strength  without  increasing  the  size  of  the  piece, 
various  elements  are  used  in  connection  with  the 
carbon.  Certain  of  these  elements  reduce  the  ten- 
dency to  break  from  repeated  stresses  and  vibration 
thus  increasing  the  life  of  the  article.  Such  steels 
require  heat  treatment  because  in  the  natural  or 
annealed  state  they  are  little,  if  any,  better  than 
plain  carbon  steels.  When  properly  heat  treated 
they  show  a  decided  improvement  in  physical  char- 
acteristics. 

Nickel  Steel. — Nickel  steel  containing  0.15  per  cent 
carbon  is  used  for  parts  that  are  to  be  case  hardened 
and  which  require  a  very  hard  suiface  with  a  tough 
strong  interior,  or  core.  It  is  especially  suited  for 
gears  that  are  to  be  case  hardened.  That  containing 


MISCELLANEOUS   WORK.  203 

0.20  to  0.25  per  cent  is  also  used  for  pieces  that  re- 
quire case  hardening,  but  the  process  must  be  adapted 
to  the  increase  of  carbon.  If  properly  treated  the 
core  will  be  stronger  than  if  a  lower  carbon  steel  was 
used. 

Nickel  steel  with  0.30  to  0.35  per  cent  carbon  is 
used,  at  times,  for  parts  that  are  case  hardened  but 
is  not  to  be  recommended.  It  is  especially  valuable 
for  such  parts  as  automobile  driving  shafts,  crank 
shafts,  axles,  etc.  The  particular  heat  treatment 
necessary  to  produce  desired  results  depends  on  the 
requirements  of  the  individual  piece.  Wide  varia- 
tions as  to  the  ultimate  strength  and  elastic  limit  are 
obtained  by  using  various  quenching  mediums,  and 
by  variations  in  temper  drawings. 

Nickel-chromium  Steels. — Steel  containing  nickel 
and  chromium  in  combination  with  carbon  is  used. 
The  percentage  of  these  elements  varies  according 
to  the  requirements  of  the  piece.  For  use  in  making 
gears  that  are  to  be  oil  hardened  the  carbon  content 
is  about  0.5  per  cent,  while,  for  those  requiring  case 
hardening  it  is  about  0.25  per  cent.  The  amount  of 
nickel  varies  from  i  to  3.5  per  cent  and  the  chromium 
from  .3  to  1.5  per  cent. 

Chrome-vanadium  Steels. — Chrome-vanadium  steel 
with  a  low  carbon  content  is  used  for  parts  that 
require  case  hardening,  and  the  carbon  should  not 
exceed  0.20  per  cent.  The  0.40  to  0.45  per  cent 
carbon  steel  is  used  where  great  strength  together 
with  toughness  is  required.  It  is  extensively  used 
for  gears,  springs  and  other  articles  that  are  to  be 
quenched  in  oil. 


204  FORGE-PRACTICE. 

Tool  Steel. — By  the  term  "tool  steel"  we  mean  the 
product  of  the  crucible  process  made  especially  for 
cutting-tool  purposes.  However,  a  large  amount  of 
crucible  tool  steel  is  used  in  making  parts  of  ma- 
chines, etc.,  and  many  times  it  is  used  where  a  good 
grade  of  open-hearth  steel  would  answer  the  purpose 
as  well  and  at  a  lower  cost.  On  the  other  hand,  con- 
siderable high  carbon  open-hearth  steel  is  used  for 
cutting  and  other  tools.  Notwithstanding  its  lower 
initial  cost  its  use  is  not  to  be  advocated  unless  those 
in  charge  have  a  knowledge  of  the  subject  that  makes 
it  possible  for  them  to  rightly  decide  as  to  what  tools 
it  is  suitable  for.  When  one  considers  that  many  dol- 
lars' worth  of  labor  may  be  expended  on  a  tool  the 
steel  in  which  costs  but  comparatively  little,  it  is  ap- 
parent that  saving  on  steel  may  be  costly  "economy." 
However,  if  a  "cheap"  steel  will  answer  the  purpose 
as  well  it  is  folly  to  buy  a  high-priced  article,  espe- 
cially where  it  is  used  in  large  quantities.  High 
price  does  not  always  mean  adaptability.  A  steel 
may  cost  many  times  as  much  as  another  that  is  far 
better  suited  for  a  given  purpose.  The  essential 
thing  to  consider  is  the  fitness  of  the  steel  for  the 
purpose  for  which  it  is  to  be  used.  When  the  right 
steel  is  to  be  had  it  should  be  procured  regardless  of 
cost. 

Tool  steel  is  made  with  a  great  range  of  carbon 
content.  Where  it  is  to  be  subjected  to  battering 
action,  or  other  severe  usage,  and  is  to  do  no  cutting, 
the  carbon  runs  from  0.60  to  0.70  per  cent,  while,  for 
cutting  tools  requiring  extreme  hardness  it  may  be 
i. 60  per  cent  or  even  higher.  The  various  per- 


MISCELLANEOUS   WORK.  2O$ 

centages  between  these  extremes  are  adapted  for 
most  tools  used  in  cutting,  pressing,  bending  and  the 
various  other  processes  involved  in  working  metals 
into  marketable  condition. 

The  high-carbon  steels  require  extreme  care  in 
the  various  heat-treating  processes,  and  their  use 
is  discouraged  by  some  on  this  account.  The  argu- 
ments advanced  against  its  use  appear  to  a  skilled 
man  without  foundation,  because  men  skilled  in  this 
branch  of  work  can  be  had  if  they  are  given  the 
necessary  inducements. 

The  higher  the  carbon  the  lower  the  critical  point 
of  the  steel.  If  the  operator  bears  this  fact  in  mind 
he  will  have  no  trouble  in  determining  the  proper 
heats  to  employ  in  forging,  annealing  and  hardening 
high-carbon  steel.  The  idea  entertained  by  some 
manufacturers  that  they  must  use  a  steel  that  fits 
the  ability  of  their  employees  seems  to  be  without 
proper  foundation.  It  is  better  to  use  steel  suited 
to  requirements,  and  then  employ  workmen  capable 
of  properly  treating  it. 

The  percentage  of  carbon  is  many  times  denoted 
by  the  term  ' '  temper. ' '  When  used  in  this  con- 
nection it  has  no  association  with  the  " letting  down" 
process  known  as  drawing  the  temper  after  harden- 
ing. The  following  table  gives  the  uses  of  steel  of 
various  carbon  contents  as  adopted  by  at  least  one 
manufacturing  concern,  and  conforms  very  closely 
to  general  usage.  It  cannot  be  regarded  as  abso- 
lutely correct  under  all  conditions,  but  answers  as 
an  approximate  guide. 


206  FORGE-PRACTICE. 

Percentage  T,     , 

of  Carbon. 

1. 60  Tools  requiring  extreme  hardness  where  toughness 
is  not  essential,  for  cutting  partially  hardened 
forgings,  etc. 

1.50         Turning  hard  metals,  turning  chilled  rolls,  etc. 

1.40  Turning  hard  metals,  corrugating  tools,  brass  working 
tools  and  where  a  fine  edge  is  required  in  connec- 
tion with  light  cuts. 

1.30  General  tools  for  lathe  work,  cold  trimming  dies,  cutting 
dies. 

1. 20  This  is  the  steel  used  more  than  any  other  for  general 
cutting  tool  purposes,  jewelers'  rolls,  small  taps, 
twist  drills,  milling  cutters  for  ordinary  cuts,  punch 
press  dies,  dinking.  dies,  screw  threading  dies. 

l.io  Taps  in  general,  axes,  saws,  wood-working  tools, 
milling  cutters  for  rough  usage,  small  punches, 
reamers,  broaches. 

i.oo         Large  milling  cutters,  drifts,  swages,  springs. 
.90         Cold  dropping  dies,  cold  chisels,  hand-driven  punches, 
punch-press  dies  and  punches  to  be  subjected  to 
rough    usage,    large   milling   cutters   to   be   pack 
hardened. 

.80         Shear    knives,    blacksmiths'    cold    chisels,    hammers, 
sledges,  tack  chisels,  boiler-makers'  tools,  hammer 
dies,  masons'  tools. 
.70         Blacksmiths'  tools  in  general,  hot  drifts,  hot  sets,  track 

tools. 

.60         Tools  to  be  used  for  hot  work  to  stand  battering,  drop 
forging    dies   for   hot   work,   hot   trimming   dies, 
flatters,  fullers,  hot  swages. 
.50        Striking  up  dies  for  hot  work  that  are  water  cooled. 

While  the  table  gives  a  general  idea  of  the  adapta- 
bility of  steels  of  various  carbons  it  is  necessary 
many  times  to  use  different  grades  to  accomplish 
some  desired  result.  For  instance,  1.20  per  cent 
carbon  steel  is  recommended  for  the  ordinary  run  of 
taps,  yet  taps  used  for  sizing  a  hole  already  threaded 
and  where  but  a  very  small  amount  of  stock  is  to  be 
removed  are  many  times  made  from  1.40  per  cent 
carbon  steel  as  it  will  retain  its  size  much  longer. 
Small  milling  cutters  that  take  light  cuts  on  pieces  of 
irregular  form  are  sometimes  made  from  1.40  per 
cent  carbon  steel.  The  use  of  higher  carbons  than 


MISCELLANEOUS   WORK.  207 

those  specified  require  the  exercise  of  extreme  care  in 
heating  and  quenching,  but  the  results  obtained 
warrant  the  extra  care  and  expense. 

Light  in  the  Hardening  Room. — The  degree  of  light 
allowable  in  a  heat-treating  room  is  of  vital  impor- 
tance, and  the  ideas  of  men  engaged  in  the  various 
branches  of  the  business  do  not  always  coincide. 
The  writer  has  visited  shops  where  the  rooms  de- 
voted to  this  work  were  absolutely  dark  except  for 
an  individual  incandescent  light  here  and  there, 
but  these  so  located  that  they  did  not  cast  any  rays 
toward  any  heating  furnace.  He  has  been  in  plants 
where  the  furnaces  were  located  in  rooms  whose  walls 
and  ceilings  were  a  mass  of  glass,  allowing  strong, 
direct  light  free  access  to  every  portion  of  the  room. 
The  former  condition  is  far  preferable  to  the  latter 
so  far  as  ability  to  discern  heats  is  concerned,  but 
objectionable  from  the  standpoint  of  the  workman's 
health. 

A  heat-treating  room  should  be  dry  and  well  ven- 
tilated, and  should  be,  so  far  as  possible,  a  comfort- 
able place  to  work  in,  but  the  lighting  system  should 
be  so  arranged  that  no  direct  or  strong  light  can 
enter  it,  and  the  light  throughout  the  room  should  be 
as  uniform  as  possible.  A  workman  engaged  at  a 
furnace  observing  heats  finds  himself  handicapped 
if  when  he  looks  away  from  his  furnace  he  finds 
that  his  eyes  encounter  a  strong  light  in  some  other 
part  of  the  room.  When  he  looks  back  at  his  work 
it  is  several  seconds  before  his  eyes  adjust  them- 
selves to  the  change.  It  might  appear  to  one  not 
intimately  conversant  with  the  heat-treating  prob- 


208  FORGE-PRACTICE. 

lem  that  the  increasing  use  of  heat-measuring  in- 
struments and  systematic  methods  of  treating  steel 
now  employed  that  the  eye  was  being  less  relied  on 
than  formerly,  such  is  not  the  case.  The  pyrometer 
and  the  systematic  time  systems  so  successfully 
employed  are  really  only  aids  to  the  workman.  The 
human  element  is  more  important  than  ever  under 
the  conditions  that  prevail,  and  their  importance 
will  increase  as  conditions  become  better  systema- 
tized. It  is  always  a  mistake  to  think  that  any 
system  or  instrument  can  take  the  place  of  brains. 
They  are  wonderful  helps,  but  never  substitutes. 

The  lighting  of  the  room  under  consideration 
should  be  scientifically  planned.  A  diffused  light 
that  is  as  constant  as  possible  should  be  obtained. 
The  exact  degree  of  light  that  will  give  the  best 
results  cannot  be  arbitrarily  stated,  but  should  be 
so  adjusted  as  to  give  best  results.  The  aim  in  a 
number  of  places  is  to  get  a  constant  light  approach- 
ing as  nearly  as  possible  what  is  known  as  twilight. 

The  advantage  claimed  for  the  totally  dark  room 
is  that  the  light  is  absolutely  constant.  This  is  true, 
but  the  many  disadvantages  resulting  from  this  con- 
dition seems  to  outweigh  the  resulting  good. 

Where  but  one  small  furnace  is  used  in  a  plant,  it 
is  customary  to  locate  it  in  a  spot  that  is  not  wanted 
for  anything  else,  regardless  of  the  fitness  of  the  loca- 
tion. It  is  necessary  many  times  to  place  a  furnace 
in  a  room  with  the  regular  metal  cutting  machines 
that  require  a  good,  strong  direct  light.  Under  such 
circumstances  it  should  be  placed  where  it  will  get 
the  least  possible  amount  of  this  light,  or  if  this  is 


MISCELLANEOUS   WORK.  2OQ 

not  possible  devise  some  way  of  shutting  the  light  off 
so  it  cannot  strike  the  furnace  or  into  it,  or  into  the 
workman's  eyes.  Thousands  of  tools  are  ruined  each 
year  because  this  precaution  is  not  taken. 

Heating  Furnaces. — Under  this  heading  we  will  con- 
sider the  various  forms  of  heating  devices  used  in 
the  ordinary  hardening  room.  The  blacksmith's 
forge  while  not  exactly  a  furnace  is  used  very  exten- 
sively in  heating  steel  for  forging  and  hardening. 
Where  many  pieces  of  a  kind  are  to  be  heated  its 
use  is  not  to  be  advocated,  as  some  form  of  furnace 
having  an  enclosed  heating  chamber  is  generally 
preferable,  but  where  but  few  pieces  of  a  given  size 
and  form  are  to  be  treated,  and  these  to  be  followed 
by  others  of  various  design  a  large,  clean  fire  pro- 
vides a  very  satisfactory  means  of  heating. 

Muffle  Furnaces. — Muffle  furnaces  were  at  one 
time  very  extensively  used  in  heating  steel  for  hard- 
ening. The  work  was  placed  in  a  muffle,  or  cham- 
ber, so  constructed  that  the  products  of  combustion 
could  not  come  in  contact  with  the  pieces  being 
heated.  As  a  result  oxidation  of  the  surfaces  was 
practically  eliminated.  As  the  heating  is  done 
entirely  by  radiation  the  cost  of  fuel  is  greatly  in 
excess  of  a  furnace  where  the  flame  comes  in  direct 
contact  with  the  work.  For  certain  kinds  of  work 
especially  small  pieces  and  those  of  intricate  shape 
the  muffle  furnace  provides  an  ideal  means  of 
heating. 

Semi-muffle  Furnaces. — In  this  type  a  chamber  is 
provided  for  the  work,  and  the  flame  circulates 
around  the  walls  for  a  distance  and  then  enters  the 


2IO  FORGE-PRACTICE. 

chamber.  The  mixture  of  fuel  flame,  and  air  is  so 
regulated  that  perfect  combustion  takes  place  before 
it  comes  in  contact  with  the  work.  This  type  of 
furnace  is  very  satisfactory  for  most  classes  of  work 
when  heating  for  annealing,  hardening,  etc. 

Direct  Flame  Furnaces. — In  heating  for  forging,  and 
where  the  steel  is  enclosed  in  boxes  when  heating  for 
case  hardening  and  the  various  heat-treating  opera- 
tions, furnaces  are  many  times  constructed  so  that 
the  flame  enters  directly  into  the  heating  chamber, 
thus  insuring  a  very  intense  heat  at  a  comparatively 
low  fuel  cost. 

The  question  often  asked  is,  "What  is  the  best 
type  of  furnace?"  There  is  no  "best"  type  of  fur- 
nace. The  kind,  size  and  design  should  conform  to 
the  character  of  the  work  to  be  treated.  Many 
excellent  furnaces  are  to  be  obtained  from  manu- 
facturers who  have  made  a  specialty  of  heat-treating 
apparatus  for  years.  When  a  furnace  that  exactly 
meets  requirements  can  be  purchased  this  course  is 
to  be  advocated.  Many  times  furnace  manufac- 
turers will  design  and  build  a  special  type  or  size  of 
furnace  at  a  figure  that  is  less  than  such  an  article 
can  be  built  for  in  a  shop  not  especially  equipped 
to  do  such  work.  At  times  it  is  possible  to  design  and 
build  a  satisfactory  furnace  in  the  shop  where  it  is 
to  be  used,  provided  those  in  charge  have  a  thorough 
knowledge  of  furnace  design. 

Furnaces  are  built  so  that  the  fuel  gases  and  blast 
enter  at  variously  located  openings  and  the  advisa- 
bility of  any  particular  design  must  necessarily 
depend  on  the  character  of  the  work  and  the  results 


MISCELLANEOUS  WORK. 


211 


desired.  Fig.  265  shows  an  under-fired  furnace,  the 
gases  entering  at  the  bottom  as  shown.  The  gas 
and  air  uniting  in  the  combustion  chamber  and  rising 
to  the  roof,  and  are  then  forced  down  onto  the  floor 
of  the  furnace.  In  this  particular  furnace  there  are 
no  walls  extending  up  from  the  floor.  If  work  is 
placed  very  near  the  edge,  excessive  heating  of  the 
portions  nearest  the  rising  gases  is  almost  sure  to 
result. 


FIG.  265. 


FIG.  266. 


Fig.  266  shows  a  design  identical  with  Fig.  265  ex- 
cept that  upright  walls  are  added,  to  prevent  the 
undesirable  results  mentioned.  The  height  of  these 
walls  is  not  material  so  long  as  they  are  high  enough 
to  prevent  uneven  heating,  and  yet  not  sufficiently 
high  to  prevent  the  gases  flowing  naturally  into  the 
chamber.  If  carried  too  high  the  gases  are  forced 
through  the  small  openings  at  high  velocity  and 
impinge  against  the  upper  portions  of  pieces  in  the 
furnace  heating  them  hotter  than  the  balance,  this  is 
especially  true  of  large  pieces  that  extend  up  well 
toward  Jjje  roof. 


212 


FORGE-PRACTICE. 


Top-fired  Furnaces. — Where  the  work  is  encased 
in  boxes  or  tubes  top-fired  furnaces  are  many  times 
used.  The  floor  should  be  thoroughly  perforated 
or  made  up  of  grates  or  bars,  or  the  bottom  portions 
of  boxes,  or  articles  being  heated  will  be  much  cooler 


FIG.  267. 

than  the  tops.  Such  furnaces  properly  designed  and 
intelligently  operated  give  good  results  at  a  compara- 
tively low  fuel  cost.  Although  if  unprotected  pieces, 
such  as  dies,  etc.,  are  to  be  heated  it  is  doubtful  if  as 
good  results  will  be  obtained  as  with  an  underfired 
furnace. 


MISCELLANEOUS  WORK. 


213 


Fig.  267  shows  a  small  furnace  used  in  heating  com- 
paratively small  pieces.  The  fuel  used  is  illumi- 
nating gas.  For  all  around  work  up  to  the  capacity 
of  the  furnace  this  is  a  very  satisfactory  type.  Fig.  268 
shows  a  furnace  designed  for  heating  reamers  and 
other  long  and  comparatively  slender  articles.  As 


FIG.  268. 

these  pieces  are  suspended  from  the  top  there  is  little 
danger  of  their  springing  when  heating.  A  coke 
burning  furnace  is  shown  in  Fig.  269.  For  certain 
purposes  this  furnace  is  very  satisfactory.  It  is  an 
especially  desirable  type  for  use  in  heating  high- 
speed steel  for  forging. 

Fuel. — Various  forms  of  fuel  are  used  in  heating 
furnaces.     Among   the   commonly   used   forms   are 


214 


FORGE-PRACTICE. 


anthracite  (hard)  coal,  bituminous  (soft)  coal,  coke, 
charcoal,  illuminating  gas,  producer  gas,  fuel  oil, 
kerosene  and  gasoline.  The  advisability  of  using 
any  certain  kind  depends  on  the  character  of  the  fur- 
nace, the  nature  of  the  work  to  be  heated,  and  the 
locality  of  the  factory. 


FIG.  269. 

In  certain  parts  of  the  country  a  particular  form  of 
fuel  may  be  difficult  to  get,  or  too  expensive  to  use. 
Where  illuminating  gas  can  be  obtained  cheaply 
we  have  a  very  satisfactory  means  of  heating  small 
furnaces.  Where  fuel  oil  can  be  easily  obtained  at 
a  reasonable  cost  we  have  one  of  the  very  best  means 
of  heating  large  furnaces,  and  it  also  works  well  for 
small  furnaces  provided  they  are  equipped  with 
suitable  burners. 


MISCELLANEOUS   WORK.  215 

Kerosene  and  gasoline  are  sometimes  used  as  fuel. 
The  cost  of  this  fuel,  however,  is  apt  to  be  greatly  in 
excess  of  fuel  oil.  Charcoal  is  used  in  the  black- 
smith's forge  for  heating  tool  steel,  while  coke  is  quite 
extensively  used  in  small  furnaces  of  different  types. 
Both  anthracite  and  bituminous  coal  are  used  in  large 
and  small  furnaces  where  the  steel  does  not  come  in 
direct  contact  with  the  fuel. 

Some  large  plants  are  provided  with  gas  producers 
used  in  making  gas  for  heating  purposes.  Furnaces 
equipped  to  burn  illuminating  gas  can  be  run  on 
this  fuel  at  a  small  cost. 

Small  furnaces  are  usually  made  of  a  height  that 
allows  a  man  of  ordinary  stature  to  observe  the 
interior  of  the  heating  chamber  without  any  special 
exertion.  Large  furnaces,  if  used  for  pieces  or  boxes 
of  ordinary  size  are  made  so  that  the  floor  of  the  fur- 
nace is  about  2  feet  above  the  floor  level  of  the  room, 
in  order  that  boxes  may  be  placed  in  the  furnace 
easily.  While  those  intended  for  heating  extra 
heavy  pieces  have  the  floor  on  the  same  level  as  the 
room  floor,  the  boxes  being  run  in  on  a  truck  of  the 
design  shown  in  Fig.  270. 

To  describe  the  ideal  furnace  for  all  around  pur- 
poses would  be  impossible,  as  the  character  of  the 
work  to  be  heated,  the  desired  results  and  the  fuel 
to  be  used  must  all  be  taken  into  consideration.  The 
writer  has  in  mind  a  hardening  plant  having  twelve 
large  furnaces  used  in  heating  steel.  Several  of 
these  are  designed  for  carburizing  work  for  case 
hardening.  These  are  run  at  temperatures  varying 
from  1650°  to  1850°  F.  while  others  are  intended  for 


2l6  FORGE-PRACTICE. 

pieces  that  are  to  be  pack  hardened  and  where 
uniform  temperatures  not  exceeding  1450°  F.  are 
desired.  One  furnace  is  used  for  pack  hardening 
high-speed  steel  and  requires  temperatures  ranging 
from  1750°  to  2250°  F.  while  others  are  used  for  all 
around  work.  Most  of  these  use  fuel  oil  for  heating, 
while  those  used  for  work  requiring  the  lower  tem- 
peratures use  hard  coal  as  fuel.  Contrary  to  the 
claims  of  many  furnace  men  it  is  found  that  very 


FIG.  270. 

uniform  results,  at  low  temperatures,  can  be  main- 
tained with  this  fuel,  under  ordinary  conditions. 

Lead  Bath. — Lead  provides  a  fairly  satisfactory 
method  of  heating  steel.  In  many  shops  it  has  given 
way  to  various  salts  which  are  lighter  and  do  not 
oxidize  as  readily.  However,  red  hot  lead  affords  a 
very  good  means  of  heating  if  certain  precautions  are 
observed.  Oxidation  of  the  surface  may  be  over- 
come to  a  degree  by  keeping  it  covered  with  pow- 
dered charcoal.  The  practice  of  using  any  old  scrap 


MISCELLANEOUS  WORK.  217 

lead  cannot  be  too  severely  condemned,  as  good 
results  can  only  be  obtained  by  using  a  brand  of  pig 
lead  known  as  "commercially  pure  lead." 

The  crucible  used  to  hold  the  lead  should  be  of 
graphite.  The  life  of  graphite  crucibles  may  be  very 
materially  lengthened  by  annealing  before  they  are 
used,  which  is  done  by  placing  in  a  furnace,  heating 
to  a  full  red,  and  then  removing  and  placing  on  top 
of  the  furnace,  or  in  some  warm  place  where  no  cur- 
rent of  air  can  strike  them,  and  left  until  cool. 

Crucibles  may  be  heated  in  a  coke  or  coal  fire,  but 
better  results  follow  the  use  of  specially  designed  fur- 
naces burning  gas  or  oil  as  shown  in  Fig.  271.  The 
burners  should  be  so  arranged  that  the  flame  will 
circulate  around  the  crucible  instead  of  impinging 
against  it.  A  piece  of  fire  brick  should  be  placed 
under  it  for  the  crucible  to  rest  on. 

After  using  and  before  cooling  the  lead  should  be 
poured  out  of  the  crucible  as  the  expansion  of  the 
metal  when  it  is  remelted  would  crack  the  crucible. 
It  is  advisable  to  cast  the  lead  into  small  blocks,  as  it 
can  be  conveniently  handled  when  recharging  the 
crucible. 

Melted  lead  has  a  tendency  to  stick  to  steel  unless 
the  surface  of  the  piece  is  coated  with  some  substance. 
There  are  several  dips  that  are  used  with  more  or 
less  satisfactory  results.  A  dip  commonly  used  is 
made  by  dissolving  i  Ib.  of  ferro-cyanide  of  potas- 
sium in  i  gal.  of  boiling  water;  when  this  cools  it  is 
ready  for  use.  Salt  is  dissolved  in  water  until  a  sat- 
urated solution  is  obtained.  A  thin  paste  of  rye 
flour  is  sometimes  used.  The  following  paste  has 


218 


FORGE-PRACTICE. 


been  used  by  the  writer  for  many  years  with  excel- 
lent results:  pulverized  charred  leather  2  parts, 
table  salt  4  parts,  wheat  flour  3  parts.  The  ingre- 
dients are  well  mixed  and  water  is  added  to  the  mix- 
ture until  it  reaches  the  consistency  of  varnish. 


FIG.  271. 

After  the  pieces  are  immersed  in  any  of  the  dips 
they  should  be  placed  where  they  will  dry  quickly. 
This  is  done  many  times  by  placing  them  on  the 
plate  on  top  of  the  furnace  and  also  serves  to  pre- 
heat the  pieces  before  they  are  placed  in  the  lead. 
Moisture  of  any  kind  must  never  be  allowed  to  get 
into  the  lead  or  particles  will  fly,  which  may  produce 


MISCELLANEOUS   WORK.  2Ip 

blindness  if  they  enter  the  eyes.  If  the  paste  men- 
tioned is  used  its  fusing  point  indicates  the  proper 
temperature  at  which  ordinary  carbon  tool  steels 
are  hardened.  As  steel  is  lighter  than  lead  articles 
to  be  heated  will  float  on  the  surface  of  the  bath 
unless  held  under  the  surface.  If  many  pieces  are 
being  treated  much  time  can  be  saved  by  using  a 
holder  of  some  form  for  this  purpose. 

Preheating  before  putting  in  the  lead  is  necessary 
for  pieces  having  large  and  small  portions  adjacent 
to  each  other. 

A  gas-fired  furnace  equipped  with  an  automatic 
heat  controller  is  shown  in  Fig.  272.  It  is  claimed  by 
the  manufacturers  that  Gas  Blast  Furnaces  operated 
with  it  will  not  vary  more  than  5°  F.  from  a  fixed 
temperature  to  which  the  instrument  is  set. 

The  instrument  consists  of  two  distinct  parts:  A 
pyrometer,  so  constructed  that  the  movement  of  the 
dial  pointer  both  indicates  and  controls  the  temper- 
ature, and  a  pneumatic  valve  attached  to  the  fur- 
nace operated  by  the  same  air  pressure  supplied  to 
the  furnace  for  combustion,  admitting  both  gas  and 
air  in  the  correct  proportion  to  maintain  the  desired 
temperature. 

While  such  a  controller  is  of  but  little  practical 
value  on  a  furnace  doing  a  variety  work  in  small  lots, 
or  which  are  made  from  varying  grades  of  steel,  its 
usefulness  where  large  batches  of  delicate  tools  are 
heated  can  hardly  be  overestimated. 

Heat-recording  Instruments. — Manufacturers  are  re- 
alizing more  and  more  the  importance  of  proper  tem- 
peratures in  the  heat  treatment  of  steel.  Modern 


220 


FORGE-PRACTICE. 


appliances  used  in  testing  the  hardness  of  materials 
show  that  a  variation  of  a  few  degrees  has  a  pro- 
nounced effect  on  the  condition  of  the  steel.  The 


FIG.  272, 


higher  the  carbon  content  the  more  pronounced  the 
effect  of  heat.  Tools  made  from  high  carbon  steels 
and  that  are  to  be  subjected  to  excessive  strains  are 


MISCELLANEOUS   WORK.  221 

found  to  be  very  much  injured,  at  times,  when 
heated  above  the  proper  temperature.  The  writer 
has  seen  cases  where  a  1.60  per  cent  carbon  steel 
heated  15°  F.  above  the  temperature  it  should  have 
received,  was  decidedly  inferior  to  that  cut  from  k  the 
same  bars  and  heated  to  the  right  temperature. 
Some  writers  claim  to  have  observed  like  results  at 
even  slighter  variations  than  noted  above.  Steel 
that  is  underheated  shows  as  great,  or  even  greater, 
variations  so  far  as  practical  results  are  concerned. 

Knowing  that  a  slight  variation  in  temperature 
leads  to  undesirable  results,  and  that  the  human  eye 
is  not  to  be  absolutely  relied  upon,  it  is  apparent 
that  in  order  to  meet  modern  requirements  articles 
made  from  high  carbon  steel  must  be  heated  under 
conditions  that  render  it  possible  to  obtain  very 
nearly  exact  temperatures. 

At  the  present  time  there  are  a  number  of  reliable 
pyrometers  on  the  market.  Any  one  of  these  will 
give  desirable  results  if  properly  installed  and  care- 
fully watched.  Like  all  delicate  instruments  and 
complicated  machinery  they  need  frequent  inspec- 
tion and  careful  testing.  Pyrometers  should  be 
calibrated  every  little  while  to  make  sure  they  are 
recording  correctly.  The  writer  knows  of  one  con- 
cern whose  chemist  tests  all  pyrometers  once  a  week ; 
in  another  factory  they  are  tested  every  other  day. 
The  frequency  with  which  these  tests  should  be  made 
cannot  be  stated  arbitrarily,  but  they  should  be 
made  whenever,  in  the  judgment  of  the  furnace  man, 
everything  is  not  exactly  right. 

A  man  whose  eyes  are  trained  to  discern  heats  can 


222  FORGE-PRACTICE. 

tell  within  a  few  degrees  the  temperature  in  a  fur- 
nace, provided  it  does  not  exceed  1800°  F.  if  light 
conditions  are  favorable.  If  the  pyrometer  reading 
does  not  closely  correspond  to  the  temperature  as 
indicated  by  practical  tests,  and  results  do  not  tally 
with  results  obtained  by  previous  treatment  under 
the  same  conditions,  no  time  should  be  lost  in  cali- 
brating the  instrument. 

The  writer's  attention  was  called  at  one  time  to  a 
large  lot  of  projectiles  that  were  giving  considerable 
trouble  when  machined.  These  pieces  were  sup- 
posed to  be  heated  to  1550°  F.  and  quenched  in 
a  bath  of  oil,  after  which  they  were  reheated  to 
1000°  F.  This  treatment  was  given  prior  to  the 
essential  .machining  operations.  Chemical  analysis 
showed  that  the  various  pieces  were  of  practically 
the  same  composition  as  former  batches  that  ma- 
chined satisfactorily.  Investigation  in  the  heat- 
treating  plant  showed,  according  to  observation, 
that  the  temperature  of  1550°  F.  was  much  ex- 
ceeded. When  tested  out  with  "sentinel  cones"  the 
pyrometer  was  found  to  register  nearly  200°  F.  out 
of  the  way.  It  was  also  calibrated  in  connection 
with  a  test  pyrometer  and  the  amount  of  variation 
noted  substantiated.  There  is  little  excuse  for  any 
such  variation  as  just  noted,  as  the  color  variation 
should  have  been  apparent  to  the  furnace  man  no 
matter  what  the  pyrometer  readings  may  have  been. 

It  is  customary  in  most  large  plants  to  have  an 
extra  pyrometer  known  as  a  "test  pyrometer" 
whose  accuracy  is  known.  This  instrument  is 
coupled  up  and  used  in  connection  with  the  regular 


MISCELLANEOUS   WORK.  223 

pyrometer  and  the  readings  compared.  In  the 
absence  of  a  test  pyrometer  sentinel  cones  may  be 
used.  These  cones  are  made  from  earthy  and 
metallic  substances  and  the  fusing  temperature  is 
marked  on  each  cone.  It  is  a  good  plan  to  have 
on  hand  a  number  of  cones  of  different  fusing 
points. 

In  making  a  test  a  cone  of  the  desired  grade  is 
placed  in  the  furnace  while  the  temperature  is  low 
and  the  heat  gradually  increased  until  the  cone 
breaks  down.  At  the  moment  it  breaks  down  note 
the  reading  of  the  pyrometer.  If  the  pyrometer 
is  used  to  denote  various  temperatures  a  number  of 
cones  having  different  fusing  points  may  be  placed 
in  the  furnace  at  a  time,  those  having  the  lowest 
and  highest  fusing  points  corresponding  with  the 
range  of  temperature  usually  indicated  by  the  pyrom- 
eter. When  making  these  tests  it  is  advisable  to 
have  two  men,  one  to  watch  the  cones  and  the  other 
the  reading  of  the  pyrometer.  When  a  cone  crumbles 
the  man  observing  it  gives  a  signal  and  the  other 
notes  the  reading. 

Sentinel  cones  are  also  useful  where  there  are  no 
pyrometers.  By  occasionally  placing  one,  whose 
predetermined  fusing  point  is  the  same  as  the  tem- 
perature to  which  the  work  should  be  heated,  in  the 
furnace  together  with  a  piece  of  steel  of  about  the 
size  and  shape  of  the  cone  and  gradually  raising  the 
temperature  of  the  furnace  until  the  cone  breaks  down. 
The  appearance  of  the  steel  should  be  carefully 
noted  at  the  instant  the  cone  crumbles.  This  prac- 
tice tends  to  keep  fixed  in  the  operator's  mind  the 


224  FORGE-PRACTICE. 

exact  temperature  to  which  he  should  heat  the  steel 
he  is  treating  to  get  desired  results. 

The  writer  would  not  be  understood  as  advocating 
the  use  of  cones  when  a  good  pyrometer  is  available, 
neither  would  he  advise  their  use  in  calibrating 
pyrometers  when  it  is  possible  to  obtain  another 
instrument  of  known  reliability,  but  in  the  absence 
of  these  the  cones  may  be  made  to  answer. 

Pure  salt  may  be  used  in  testing  pyrometer  read- 
ings. Insert  the  thermo-couple  in  a  small  crucible 
containing  pure  salt  and  heat  the  salt  to  1600°  F. 
Remove  the  crucible  from  the  furnace  and  allow  it  to 
cool.  At  the  freezing  point  of  salt,  which  is  1472°  F. 
or  800°  C.,  note  the  pyrometer  reading.  When  the 
salt  is  cooled  to  the  freezing  point  the  temperature 
remains  fairly  constant  for  a  short  time,  after  which 
the  cooling  down  to  normal  is  fairly  uniform. 

The  melting  point  of  several  different  metals  may 
be  satisfactorily  employed  for  checking  pyrometers. 
The  melting  points  of  those  most  generally  used  for 
this  purpose  are  as  follows : 

Tin 450°  F. 

Zinc 787°  F. 

Silver 1761°  F. 

In  many  cases  each  furnace  is  provided  with  a 
pyrometer,  while  under  different  conditions  a  num- 
ber of  furnaces  are  connected  to  one  pyrometer,  each 
furnace  reading  being  obtained  by  means  of  a  switch. 
When  working  under  the  latter  condition  each  fur- 
nace must  be  numbered  and  the  switch  thrown  to  a 
pole  corresponding  to  the  number  of  the  furnace 


MISCELLANEOUS  WORK. 


225 


whose  temperature  is  to  be  read.     Such  a  switch- 
board is  shown  in  Fig.  273. 

In  some  large  heat-treating  plants  a  central  pyrom- 
eter is  maintained ;  this  is  connected  with  the  various 
furnaces,  and  is  in  charge  of  an  operator  who,  by 
means  of  various  colored  lights  located  on  each  fur- 
nace, signals  the  furnace 
man  regarding  his  heats. 
Three  electric  lights  are 
on  each  furnace.  The  red 
light  burns  when  the  temp- 
erature is  too  low,  the  white 
light  when  the  tempera- 
ture is  within  the  accepted 
limits,  and  the  green  light 
when  the  temperature  is 
too  high. 

Fig.  274  shows  an  Auto- 
matic Signaling  Equipment 
which  is  attached  to  the 
furnace  and  is  directly  con- 
trolled by  the  furnace  temperature, 
with  the  central  pyrometer. 

In  Fig.  275  is  shown  a  thermo-couple  immersed  in  a 
pot  of  molten  lead.  The  application  is  the  same  if 
other  metals,  or  salts  are  used  in  the  bath. 

In  many  large  plants  where  the  amount  of  work 
warrants  the  outlay  recording  pyrometers  are  in- 
stalled in  the  office  of  the  superintendent,  or  other 
official.  These  instruments  indicate  and  record  the 
furnace  temperatures,  whereby  it  is  possible  for  those 
in  charge  to  keep  records  of  the  temperatures. 


FIG.  273. 


This  does  away 


226 


FORGE-PRACTICE. 


Baths. — There  are  many  forms  of  baths  used  in 
hardening,  and  an  almost  endless  number  of  liquids 


FIG.  274. 

and  mixtures  for  cooling.  The  particular  form 
desirable  depends  on  the  nature  of  the  work  to  be 
cooled. 


FIG.  275. 

A  pail,  barrel,  or  tank  answers  very  well  for  many 
kinds  of  work,  and  is  entirely  unsuited  for  others. 
Where  but  a  few  small  pieces  are  to  be  hardened  a 


MISCELLANEOUS   WORK. 


227 


FIG.  276. 


small  vessel  may  be  used,  but  larger  pieces  require  a 
generous  quantity  of  liquid  to  do  away  with  change 
of  temperature.  Where  many 
pieces  are  to  be  done  in  succession 
some  means  must  be  provided  to 
keep  the  bath  at  an  even  temp- 
erature. At  other  times  it  is 
necessary  to  project  the  liquid 
against  some  certain  portion  of 
the  piece. 

A  common  form  of  bath  hav- 
ing a  jet  coming  up  from  the 
bottom  is  shown  in  Fig.  276.  If 
a  certain  temperature  is  not 
essential  the  inlet  pipe  may  be 
connected  with  the  street  main,  or  some  other  source 
of  supply.  An  overflow  pipe  larger  than  the  inlet 
must  be  provided,  as  shown. 

If  brine,  oil  or  some  favorite  mixture  is  used  the 
liquid  may  be  taken  as  it  comes  from  the  overflow 
and  pumped  to  a  tank  located  a  few  feet  above  the 
bath.  A  pipe  from  this  tank 
allows  the  liquid  to  return  to  the 
bath  by  gravity.  Where  there 
is  danger  of  the  liquid  becoming 
heated  a  bath  of  the  design 
shown  in  Fig.  277  is  used.  The 
liquid  is  drawn  from  the  bath  by 
means  of  a  pump  and  forced 
through  coils  of  pipe  in  an  outer  tank  and  returned  to 
the  bath  as  shown.  This  form  may  have  many  modi- 
fications. The  writer  knows  of  one  hardening  plant 


FIG.  277. 


228 


FORGE-PRACTICE. 


located  on  the  bank  of  a  river  where  the  cooling 
coils  are  run  into  the  river  at  some  distance  below 
the  surface.  This  is  necessary  as  many  large  pieces 
are  hardened  in  the  bath  every  day. 

For  an  all  around  bath  for  many  kinds  of  work  the 
form  shown  in  Fig.  278  is  excellent.  The  general 
design  may  be  planned  to  meet  the  needs  of  the 

individual  shop.  There 
are  six  or  more  pipes  up 
the  sides  of  the  tank  which 
are  perforated  in  such  a 
manner  that  the  water  or 
other  fluid  is  projected 
toward  the  center.  If  it 
is  desired  it  may  be  so 
arranged  as  to  have  the 
pipes  swing  toward  the 
center  when  hardening 
small  pieces.  The  center 
pipe  is  much  shorter  and 
open  at  the  top  to  allow 
the  liquid  to  flow  toward 
the  surface.  This  form  of 
bath  is  invaluable  for  such 
work  as  drills,  taps  and 

other  pieces  having  grooves  or  flutes,  as  the  liquid  is 
able  to  reach  every  part  of  the  surface.  The  liquid 
projected  through  the  holes  in  the  upright  pipes 
against  the  irregular  surface  prevents  the  steam, 
resulting  from  the  contact  of  red  hot  metal  and  the 
fluid,  from  pocketing  at  any  point. 

When  hardening  cylindrical-shaped  pieces  whose 


MISCELLANEOUS   WORK.  22Q 

ends  as  well  as  circumference  must  be  hard,  this 
bath  will  be  found  most  effective  as  a  pipe  may  be 
added  above  the  tank  and  a  jet  thrown  downwards. 
This,  together  with  the  jet  coming  up  from  the  bot- 
tom, insures  the  hardening  of  the  walls  of  counter- 
sunk center  holes  in  such  pieces  as  lathe  mandrels, 
etc. 

In  many  instances  the  hardening  of  the  entire 
surface  of  the  cylindrical  pieces  without  having  here 
and  there  soft  spots  is  found  to  be  a  difficult  matter. 
The  use  of  this  bath  properly  arranged  will  obviate 
this  difficulty. 

When  work  is  heated  in  hardening  boxes  and 
dumped  into  a  bath  ununiform  results  are  many 
times  obtained  as  the  pieces  go  into  the  bath  in  a 
body  and  slow  cooling  of  some  pieces  follow.  A  form 
of  bath  that  obviates  this  difficulty  is  shown  in  Fig. 
279  where  wires  are  arranged  so  as  to  separate  the 
pieces  and  cause  them  to  rotate  as  they  descend. 
The  depth  of  the  bath  should  be  such  that  the  pieces 
will  be  cooled  below  a  red  before  reaching  the  bot- 
tom, or  an  agitator  may  be  provided  to  keep  them  in 
motion  until  cool. 

Fig.  280  represents  a  bath  that  is  many  times  used 
with  good  results  when  hardening  pieces  of  various 
forms.  The  work  travels  down  the  inclined  shelves, 
rolling  over  and  over  until  the  bottom  is  reached. 

Ball-shaped  pieces  are  difficult  to  harden  in  a 
bath  of  ordinary  construction,  but  show  uniform 
results  when  quenched  in  one  of  the  designs  shown 
in  Fig.  281.  The  depth  of  the  tank  must  conform  to 
the  size  of  the  pieces,  although  a  deep  tank  insures 


230 


FORGE-PRACTICE. 


good  results  on  both  large  and  small  work.  The 
false  bottom  (a)  may  be  of  wire  netting  of  a  size 
that  will  not  allow  the  piece  to  pass  through.  The 
liquid  must  enter  at  the  bottom  with  sufficient  force 
to  prevent  the  pieces  resting  on  the  netting  which, 
being  inclined,  causes  them  to  move  toward  the 

Overflow  Pipe 


^^^ 


lower  portions  from  which  they  drop  into  the  per- 
forated tray.  The  tray  being  removable  may  be 
raised  occasionally  and  the  pieces  taken  away. 

At  times  it  is  necessary  to  harden  pieces  of  a  size 
that  do  not  show  good  results  when  immersed  in  a 
body  of  water,  and  which  may  be  hardened  satis- 
factorily if  one  or  more  large  streams  of  water  are 


MISCELLANEOUS   WORK. 


23I 


projected  against  the  portions  desired  hard.  Take, 
for  instance,  the  block  shown  in  Fig.  282  which  is 
about  10"  in  diameter  and  6"  long.  The  projecting 
ends  must  be  hard  while  it  is  immaterial  whether 
the  balance  of  the  block  is  hard  or  soft.  Repeated 
efforts  to  harden  in  a  body  of  water  where  large, 


FIG.  280. 

strong  jets  were  projected  against  the  ends  resulted 
in  failure  as  steam  was  generated  in  such  quantities 
that  the  water  could  not  act  on  the  portions  desired 
hard.  Excellent  results,  however,  were  obtained 
when  the  pieces  were  suspended  and  heavy  streams 
of  water  projected  against  the  ends  as  shown  in  Fig. 
283.  By  the  use  of  this  device  the  steam  readily 
escaped  into  the  air  and  did  not  retard  the  cooling 


232 


FORGE  PRACTICE. 


action  of  the  water.  This  method  of  cooling  may 
be  modified  to  meet  various  conditions.  In  con- 
nection with  the  streams  against  the  ends,  pipes 
may  be  provided  so  as  to  force  water  against  all  por- 
tions of  the  piece  if  desirable. 


FIG.  281. 

While  we  have  given  several  designs  of  baths,  some 
of  which  are  intended  for  general  use,  and  others  for 
special  kinds  of  work,  it  is  many  times  necessary  to 
make  baths  of  a  design  that  will  accomplish  a  spe- 
cific result.  It  would  not  be  possible  to  anticipate 
every  requirement,  and  those  in  charge  of  heat- 


MISCELLANEOUS    WORK. 


233 


treating   departments   must   invent  something  that 
will  insure  the  desired  result. 


FIG.  282. 


While  clear  water  is  the  medium  most  often  used 
in  baths,  better  results  follow  the  use  of  other  fluids 
at  times,  as  for  instance,  brine  which  is  a  solution  of 


FIG.  283. 

salt  and  water.  The  amount  of  salt  varies  accord- 
ing to  the  result  to  be  attained,  ranging  from  a  small 
amount  to  enough  to  produce  a  saturated  solution. 
Borax,  alum,  ammonia,  cyanide  of  potassium,  cor- 


234  FORGE-PRACTICE. 

rosive  sublimate,  citric  acid,  sulphuric  acid  and 
numerous  other  things  are  sometimes  used.  The 
use  of  cyanide  and  corrosive  sublimate  or  any  other 
violent  poison  is  not  advocated  on  account  of  the 
possibility  of  fatal  results  to  those  using  them. 
While  a  solution  of  sulphuric  acid  and  water  many 
times  insures  a  surface  superior  to  that  obtained  by 
other  mediums,  its  use  is  not  advocated  for  articles 
that  are  not  to  be  used  and  discarded  within  a  short 
time,  as  it  "rots"  the  steel.  Dies  and  similar  tools 
hardened  in  this  bath,  and  laid  away  for  a  time,  will 
be  found  worthless.  It  is  claimed  that  steel  hard- 
ened in  this  solution  and  then  reheated  to  650°  F. 
will  show  no  bad  results,  but,  reheating  to  this 
temperature  softens  cutting  tools  so  they  are  useless. 

For  some  classes  of  milling  machine  cutters  and 
similar  tools  a  bath  of  water  having  on  its 'surf  ace  a 
thin  layer  of  oil  is  valuable.  The  steel  plunged 
through  the  oil  has  a  thin  coating  of  oil  adhering  to 
it,  which  retards  the  cooling  action  of  the  water  to  a 
certain  degree,  thus  preventing  the  tendency  to 
crack  from  too  rapid  contraction. 

Oil  is  much  slower  in  action  than  water,  and  heated 
steel  plunged  into  it  has  less  tendency  to  warp  or 
crack.  Unfortunately,  pieces  made  from  carbon 
steel,  unless  quite  small  or  thin,  do  not  harden  suf- 
ficiently for  most  purposes  when  quenched  in  it. 
However,  articles  of  certain  size  and  shape  will 
harden  nicely  in  it  and  when  it  will  give  the  desired 
hardness  its  use  is  to  be  advocated. 

All  oils  are  not  alike  in  their  ability  to  extract  heat 
from  steel,  consequently  different  kinds  are  used 


MISCELLANEOUS   WORK.  235 

to  give  a  variety  of  results.  Lard  oil  is  used  many 
times  where  toughness  is  desirable  rather  than 
hardness.  Raw  linseed  oil,  sperm  oil,  cotton-seed 
oil,  fish  oil  and  the  various  hardening  and  tempering 
oils  are  used  either  alone  or  mixed  with  one  another, 
or  with  light  mineral  oils. 

At  times  borax,  alum,  soda,  turpentine,  beeswax 
and  various  other  ingredients  are  placed  in  oil  used 
in  hardening.  The  use  of  turpentine,  kerosene,  or 
other  ingredients  having  a  low  "flashing"  point  as 
an  admixture  is  hardly  to  be  advocated  unless  the 
party  using  it  is  thoroughly  versed  in  its  action,  and 
is  provided  with  equipment  that  makes  their  use 
safe.  Serious  burns,  loss  of  life  and  property  have 
resulted  from  some  unwise  attempts  to  follow  some 
published  statement  of  extraordinary  results  ob- 
tained. 

It  is  found  possible  at  times  to  mix  a  heavy  animal 
oil  and  a  light  mineral  oil  and  produce  good  results 
in  cases  where  neither  one  alone  gave  satisfaction. 

Water. — Water  is  used  more  than  any  other  liquid 
as  a  medium  for  quenching  red-hot  steel  in  the 
process  of  hardening.  Where  but  a  small  quantity 
is  used  in  a  still  bath,  it  is  undoubtedly  true  that  best 
results  follow  the  use  of  rain  water,  or  of  boiled  water. 
Where  it  is  necessary  to  provide  a  constant  supply 
of  fresh  water  it  is  customary  to  connect  directly 
with  a  water  main,  or  to  pump  from  a  stream  or  well. 
In  such  cases  it  is  necessary  to  use  the  water  without 
regard  to  its  purity  or  its  fitness  for  the  work.  One 
objection  to  such  conditions  is  the  varying  tempera- 
ture of  water  from  mains  or  rivers,  and  the  extreme 


236 


FORGE-PRACTICE. 


coldness  of  that  from  wells,  especially  artesian  wells. 
Water  from  the  two  former  sources  varies  in  tem- 
perature according  to  the  seasons. 

As  extremely  cold  water  should  seldom  be  used  for 
pieces  of  intricate  shape,  and  as,  in  most  cases,  it 

does  not  work  as  well  as 
when  at  a  temperature  of 
70°  F.,  it  is  advisable  to 
provide  some  means  of 
raising  it  to  the  desired 
temperature  before  it  en- 
ters the  bath.  This  may  be 
accomplished  by  connect- 
ing a  steam  supply  pipe 
with  the  inlet  pipe,  and  by 
adjusting  the  flow  of  the 
steam  by  means  of  a  valve 
so  that  the  incoming  water 
will  be  of  the  proper  temp- 
erature. In  a  factory 
manufacturing  tableware, 
such  as  spoons,  forks,  etc., 
it  was  found  that  the 
dies  used  in  striking  up 
this  work  showed  a  ten- 
dency to  crack  when  quenched.  It  was  found  that 
the  bath,  which  was  quite  ingenious  in  design,  was 
supplied  with  water  from  an  artesian  well  and  was 
extremely  cold.  A  steam  pipe  was  connected  with 
the  supply  pipe  as  shown  in  Fig.  284  and  the  water 
heated  to  from  60°  to  70°  F.  before  striking  the  heated 
dies,  as  a  result  the  cracking  was  eliminated  and  the 


Water 
Supply 


FIG.  284. 


MISCELLANEOUS   WORK.  237 

dies  were  found  to  stand  up  as  well  or  better  than 
before. 

It  will  be  seen  that  the  quenching  device  in  Fig.  284 
was  made  up  of  two  pipes,  the  outer  one  somewhat 
larger  than  the  inner.  The  inner  pipe  had  holes 
drilled  through  its  walls  so  that  the  water,  under  the 
pressure  of  the  pump,  would  pass  through  and  strike 
the  die  held  in  the  inner  pipe,  which  was  made  to 
act  as  a  drainage  pipe.  The  water  was  conducted 
away  fast  enough  so  that  there  was  no  body  of  water 
in  the  inner  pipe.  As  the  water  was  projected  in 
numerous  jets  all  vapor  was  carried  away  and 
could  not  pocket  at  any  part  of  the  die.  A  modi- 
fication of  this  form  of  bath  could  be  successfully 
applied  to  many  classes  of  work  where  steam  causes 
soft  spots  by  collecting  at  some  essential  portion 
when  work  is  immersed  in  a  body  of  water. 

It  is  undoubtedly  true  that  a  deep  penetration 
can  be  obtained  by  the  use  of  the  design  just  con- 
sidered. Experienced  hardeners  know  that  jets  of 
water  properly  applied  are  more  effective,  especially 
in  the  case  of  large  pieces,  than  a  body  of  water  even 
when  the  latter  is  of  generous  proportions. 

Use  of  Salt. — There  are  pieces  that  do  not  show  up 
favorably  when  quenched  in  brine  because  of  its 
drastic  action  on  the  steel  and  yet  when  quenched 
in  water  do  not  seem  to  show  a  uniform  surface  hard- 
ness, occasioned  probably,  by  a  slight  oxidation  of 
the  surface.  This  oxide  not  scaling  off  uniformly 
does  not  allow  the  water  to  attack  the  surface  at  all 
points  as  it  should.  In  such  cases  a  handful  of  fine 
table  salt  sprinkled  on  the  surface  of  the  bath  at 


238  FORGE-PRACTICE. 

the  moment  the  piece  is  immersed  will  work  wonders, 
as  it  causes  the  oxide  to  scale  off,  thus  leaving  a  clean 
surface  for  the  water  to  act  on. 

Many  times  where  a  brine  bath  does  not  work 
well  a  weaker  solution  of  salt  and  water  will  be  found 
to  work  satisfactorily.  The  amount  of  salt  will 
depend  on  the  character  of  the  work.  If  the  article 
to  be  hardened  is  made  of  high-carbon  steel  a  weaker 
solution  should  be  used  than  for  one  containing  less 
carbon. 

Quenching  with  Steam,  Vapor  and  Water  Sprays.— 
There  are  conditions  under  which  pieces  will  harden 
more  uniformly  and  satisfactorily  if  quenched  in  the 
open  by  means  of  jets  of  steam,  or  vapor,  or  by  sprays 
of  water  so  arranged  that  all  portions  desired  hard 
will  be  acted  on  by  the  quenching  medium. 

The  hardener  in  a  plant  doing  job  work  encounters, 
occasionally,  pieces  that  do  not  harden  well  when 
dipped  in  a  bath.  Sometimes  the  shape  is  such  that 
in  spite  of  any  arrangement  of  supply  pipes  steam 
will  pocket  at  some  point  and  retard  the  action  of  the 
cooling  medium.  The  same  piece  if  cooled  in  the 
open  air  by  means  of  properly  arranged  streams  of 
steam,  vapor,  or  water  jets,  will  harden  well  as  the 
steam  can  readily  escape  into  the  atmosphere.  At 
times  very  light  pieces  are  hardened  by  means  of 
jets  of  air,  or  by  a  volume  of  air;  the  air,  however, 
should  not  be  under  very  great  pressure  as  volume 
rather  than  velocity  counts  in  cases  of  this  kind. 
However,  on  account  of  the  oxidizing  action  of  air  on 
hot  steel  its  use  is  not  to  be  advocated  unless  the  work 
is  done  by  one  entirely  familiar  with  the  process. 


MISCELLANEOUS   WORK.  239 

Hardening.— Steel  is  hardened  by  heating  to  a 
red  and  plunging  in  some  cooling  bath.  The  par- 
ticular cooling  medium  must  depend  on  the  size  and 
shape  of  the  piece,  on  the  use  to  which  it  is  to  be  put 
and  also  upon  the  composition  of  the  steel  from 
which  it  is  made. 

The  commonly  used  baths  are  water,  brine,  and 
water  containing  some  substance  such  as  borax, 
alum,  etc.,  oil,  tallow,  or  some  of  the  so-called  fats. 
This  subject  is  more  fully  taken  up  under  the  subject 
of  baths. 

The  exact  temperature  to  which  steel  must  be 
heated  to  harden  cannot  be  stated  arbitrarily,  as  a 
tool  having  slender  portions  easily  acted  on  by  the 
bath  need  not  be  given  as  high  a  temperature  as  a 
large  bulky  piece,  but  in  no  case  should  it  be  heated 
hotter  than  is  necessary  to  produce  the  desired  re- 
sult, as  temperatures  that  are  higher  than  necessary 
perceptibly  weaken  steel. 

When  one  considers  the  enormous  strain  to  which 
the  cutting  edge  of  a  tool  is  subjected  when  in  use  it 
will  be  seen  that  the  maximum  of  strength  is  essen- 
tial. 

The  necessity  of  uniformly  heating  steel  is  more 
pronounced  when  hardening  than  with  any  of  the 
other  heat-treating  processes.  It  is  absolutely  es- 
sential that  no  portion  of  the  piece  be  overheated  as 
this  will  produce  an  ununiform  grain  and  the  over- 
heated portion  will  be  weakened  even  though  it  is 
allowed  to  cool  to  the  temperature  of  the  balance  of 
the  piece  before  quenching  in  the  bath. 

When  a  die  (Fig.  285)  is  heated  too  rapidly  in  the 


240 


FORGE-PRACTICE. 


fire  the  corners  and  edges  are  overheated.  When  the 
piece  is  quenched  in  the  bath  it  cracks,  or  the  over- 
heated portions  break  off  as  shown.  If  for  any  rea  • 
son  any  portion  of  a  tool  becomes  overheated,  it 
should  be  removed  from  the  fire  and  allowed  to  cool. 
It  may  then  be  reheated  for  hardening. 

While  steel  should  never  be  overheated,  there  is 
less  danger  of  permanently  harming  it  from  so  doing, 
than  if  most  of  it  was  brought  to  the  proper  tem- 
perature and  the  balance  overheated.  It  is  safe  to 
say  that  a  large  percentage  of  the  troubles  experi- 


FIG.  285. 

enced  when  hardening  are  due  to  the  fact  that  the 
steel  is  not  heated  uniformly. 

It  is  essential  that  the  cooling  of  a  piece  of  steel  in 
hardening  should  be  as  uniform  as  possible.  During 
the  cooling  process  contraction  takes  place;  if  the 
contraction  is  too  ununiform  the  steel  will  be  torn 
apart.  If  one  portion  cools  rapidly  and  becomes 
hard  and  unyielding  while  the  portion  next  to  it 
continues  contracting  it  is  almost  sure  to  crack. 

For  this  reason  it  is  necessary  many  times  to 
retard  the  cooling  of  some  section,  which  may  be 
done  by  covering  the  portion  to  be  cooled  slowly, 


MISCELLANEOUS  WORK. 


241 


with  a  previously  prepared  piece  of  iron,  or  smearing 
it  with  oil  or  soap  while  red  hot  and  just  before  it  is 
quenched.  Examples  of  this  practice  will  be  shown 
under  ''Hardening  Dies." 

At  times  the  inequality  of  contraction  may  be 
overcome  by  dipping  a  heavier  section  first,  then 
gradually  immersing  the  lighter  portion  as  shown  in 
Fig.  286  where  an  axe  is  being  dipped  in  the  bath. 


FIG.  286. 

It  is  a  mistake  to  assume  that  extremely  cold  baths 
are  always  necessary,  for  while  the  degree  of  hard- 
ness depends  on  how  quickly  the  heat  is  extracted, 
extremely  cold  baths  do  not  always  absorb  heat  from 
steel  as  rapidly  as  those  that  are  not  as  cold,  and 
the  shock  to  the  steel  is  not  nearly  as  great  if  the 
chill  is  removed  from  the  quenching  fluid. 

For  many  classes  of  work,  baths  that  are  at  a 
temperature  of  from  80°  to  100°  F.  are  found  to  give 


242  FORGE-PRACTICE. 

excellent  results,  while  for  thin  pieces  where  extreme 
hardness  is  not  essential  and  toughness  is  desirable, 
the  contents  of  the  bath  may  be  considerably  warmer 
than  the  temperature  mentioned. 

Testing  for  Hardness. — The  methods  formerly 
employed  in  hardness  tests  consisted  in  trying  the 
surface  with  a  file,  and  the  depth  of  penetration  with 
a  center  punch,  these  in  connection  with  the  obser- 
vation of  the  fracture  of  an  occasional  piece  made  it 
possible  for  the  skilled  man  to  work  within  the  former 
allowable  limits.  To-day  the  demands  on  the 
finished  product  make  it  necessary  to  use  more 
reliable  methods  of  testing. 

To  be  sure  the  Brinnel  Ball  Indenting  Machine 
and  several  similar  devices  were  used  in  an  occa- 
sional laboratory,  and  excellent  results  were  and 
are  obtained  by  these  systems  when  in  the  hands  of 
expert  mathematicians  experienced  in  this  particular 
line  of  work,  but  they  are  of  little  value  in  the 
ordinary  plant.  It  is  generally  accepted  that  the 
perfect  tool  must  have  a  hardness  three  times  that  of 
the  metal  it  is  to  cut.  To  obtain  this  necessary 
hardness  one  must  know  that  the  proper  tempera- 
ture cannot  be  exceeded  when  hardening,  or  excessive 
brittleness  will  result.  To  overcome  this  brittle- 
ness  the  temper  must  be  drawn  to  a  degree  that 
makes  the  tool  too  soft  to  accomplish  desired  results. 
By  means  of  the  "scleroscope"  it  is  possible  to 
measure  the  degree  of  hardness,  and  also  to  ascer- 
tain whether  the  steel  has  been  properly  heated. 

Steel  of  a  certain  carbon  content  hardened  at  the 
proper  temperature  should  show  a  certain  sclero- 


MISCELLANEOUS   WORK.  243 

scope  reading.  It  is  customary  in  some  shops  to 
take  a  test  piece  from  a  bar  of  steel  from  which  a 
number  of  costly  tools  are  to  be  made.  The  test 
piece  is  hardened  under  the  very  best  of  conditions 
by  a  skillful  hardener  and  the  degree  of  hardness 
found  by  means  of  the  "scleroscope."  A  record  is 
made  of  the  reading,  and  when  the  tools  are  hard- 
ened it  is  used  in  determining  whether  they  are  in 
the  best  possible  condition. 

The  Shore  Scleroscope  consists  of  a  small  hammer 
whose  striking  point  is  a  diamond  of  rare  cleavage 
formation  whose  striking  surface  is  slightly  rounded. 
This  hammer  works  in  a  vertical  tube  as  shown  in 
Fig.  287.  Graduations  which  read  from  o  to  140  are 
provided.  The  operation  of  the  machine  is  so 
simple  that  it  can  be  successfully  used  by  anyone 
who  has  sufficient  intelligence  to  enable  him  to  work 
in  a  heat-treating  room.  The  hammer  is  raised 
to  the  top  of  the  instrument  by  pressing  a  bulb  as 
shown  in  Fig.  288  where  the  instrument  is  being  used 
in  testing  a  projectile.  When  the  hammer  reaches 
the  top  of  the  tube  it  engages  with  a  hook  which 
holds  it  suspended.  The  leveling  rod  at  the  right  of 
the  scale  Fig.  287  enables  the  operator  to  determine 
when  the  instrument  is  plumb,  adjustment  is 
effected  by  means  of  the  knurled  leveling  screws. 
The  hammer  is  released  by  again  pressing  the 
bulb  and  drops  to  the  work.  The  rebound  of 
the  hammer  indicates  the  degree  of  hardness  of 
the  piece. 

The  surface  that  is  to  receive  the  blow  must  be 
perfectly  smooth  in  order  to  insure  correct  readings. 


244 


FORGE-PRACTICE. 


Instructions  accompany  the  instrument  and  should 
be  followed  as  closely  as  possible. 

The  hardness  of  i  per  cent  carbon  tool  steel  prop- 

: 


IV 


I 


FIG.  287. 

erly  treated  is  about  100 ;  go  is  a  low  value  and  1 10  is 
considered  high. 

As  previously  stated  it  is  generally  accepted  that 
the  perfect  tool  must  have  a  hardness  three  times 


MISCELLANEOUS  WORK.  245 

that  of  the  metal  it  is  to  cut.     Unannealed  tool  steel 
of  i  per  cent  carbon  content  is  found,  by  test,  to 
have  a  hardness  of  from  40  to  45  points.     According 
to  the  rule  just  quoted  a  tool  could  not  be  hardened 
so  as  to  cut  this  satisfactorily;    however,  the  same 
steel  properly  annealed  shows  a  hardness  of  only 
30  to  31  points,  and  as  a  tool  made  from  i  per  cent 
carbon      steel     properly 
hardened     should     show 
95    points,   or  better,    it  f\ 

becomes  an  easy  matter 
to  produce  satisfactory 
results.  From  the  ex- 
ample just  cited  it  is 
apparent  that  the  instru-  fc^J> — J 

ment  can  be  used  to  de- 
termine whether  steel  is 
properly  annealed.  In 
this  way  thousands  of 
dollars  can  be  saved  in 
cutting  tools  if  the  an- 
nealed product  is  tested  FIG.  288. 
before  machining. 

High-speed  steel  when  hardened  does  not  show  as 
high  hardness  test  as  good  grades  of  carbon  tool  steel. 
The  effectiveness  of  high-speed  steel  does  not  depend 
altogether  on  its  hardness,  but  rather  on  the  fact 
that  it  does  not  lose  its  ability  to  cut  when  heated 
to  temperatures  that  would  entirely  soften  carbon 
steels. 

The  writer  earnestly  advises  men  engaged  in  the 
heat  treatment  of  steel  to  make  a  study  of  the  testing 


246  FORGE-PRACTICE. 

of  materials.  Not  only  is  it  possible  to  accurately 
determine  the  quality  of  the  annealed  or  hardened 
product,  but  it  is  also  possible  to  determine  whether 
steel  has  been  overheated,  or  underheated,  or  un- 
uniformly  heated,  by  the  use  of  the  instrument  we 
have  been  considering. 

By  finding  the  hardness  of  a  metal  to  be  machined, 
it  is  possible  to  determine  the  carbon  content  of  a 
steel  for  use  in  making  tools  for  machining  it.  The 
uses  to  which  the  instrument  can  be  put  are  so 
numerous  and  varied  that  a  volume  could  be  written 
on  this  subject. 

Tempering. — Hardening  steel  sets  up  brittleness 
and  strains.  Tempering  is  resorted  to  to  remove 
these.  The  temper  of  a  piece  should  never  be 
drawn  any  lower  than  is  absolutely  necessary  as  the 
operation  softens  the  steel.  The  process  of  temper- 
ing is  carried  on  by  heating  the  hardened  steel  until 
the  brittleness  is  reduced  the  right  amount,  and 
this  is  determined  by  the  amount  of  heat  it  absorbs. 
This  heating  is  done  by  various  means. 

Color  Method. — When  tools  and  other  articles  are 
tempered  by  the  color  method,  the  amount  of  heat 
absorbed  by  the  steel  is  determined  by  the  colors 
on  the  surface  due  to  a  thin  film  of  oxide  which 
forms  when  the  temperature  reaches  420°  F.  and 
changes  in  color  as  the  heat  increases.  In  order  to 
see  these  colors  the  surface  of  the  hardened  steel 
must  be  brightened  by  some  means.  Most  hard- 
eners provide  themselves  with  a  buff-stick,  which  is 
a  piece  of  wood  with  emery  cloth  attached.  The 
steel  is  heated  over  a  fire,  or  on  an  iron  plate  over  a 


MISCELLANEOUS   WORK. 


247 


gas  jet,  or  on  a  piece  of  very  hot  metal,  or  by  any 
convenient  way. 

Temper  Colors. — While  the  color  method  is  not  the 
most  accurate,  it  provides  a  convenient  way  that 
answers  very  well  where  but  a  few  pieces  are  to  be 
done.  When  the  heated  piece  reaches  a  tempera- 
ture of  430°  F.,  a  very  pale  yellow  is  visible  on  the 
polished  surface.  Every  few  degrees  of  heat  causes 
changes  in  the  colors  as  set  forth  in  the  accompanying 
table: 

TEMPER  COLORS 


Color. 

Degrees  F. 

Degrees   C. 

Very  pale  yellow 

41O 

221 

Bright  yellow. 

4.4.O 

227 

Pale  straw  yellow 

A  CQ 

272 

Straw  yellow.  . 

46O 

218 

Deep  straw 

4.7O 

2/17 

Dark  straw 

4.8O 

2  /in 

Yellow  with  brown    .  . 

4.QO 

2C/1 

Brown.  .    .  . 

5OO 

26O 

Brown  with  red  spots. 

CTQ 

266 

Brown  with  purple  spots.  .  . 

C.2O 

271 

Light  purple.  .  .    . 

C7O 

277 

Full  purple  

cjx) 

282 

Dark  purple.  .  .    . 

CCO 

288 

Light  blue  

c,6o 

2Q7 

Blue   

cyo 

2QQ 

Dark  blue  

6OO 

116 

Blue  tinged  with  green   

670 

772 

Baths  for  Tempering. — A  bath  of  oil  provides  a 
very  satisfactory  method  of  tempering  where  many 
pieces  are  to  be  heated  or  where  the  nature  of  the 
articles  renders  the  use  of  the  color  method  inad- 
visable. The  pieces  are  placed  in  a  perforated  pail 
which  is  suspended  in  a  kettle  of  oil  placed  over  a 
fire,  or  in  the  regular  oil  tempering  furnace  as  in 


248 


FORGE-PRACTICE. 


Fig.  289.  The  temperature  of  the  oil  is  gauged  by 
means  of  a  thermometer.  If  the  pieces  are  large, 
or  have  some  sections  heavier  than  others,  the  tem- 
perature of  the  oil  should  be  raised  gradually  to  insure 
uniform  results.  The  oil  should  be  agitated  fre- 
quently, being  careful  that  none  is  thrown  outside 

of  the  kettle.  The 
kettle  should  be  pro- 
vided with  a  cover 
which  has  a  long 
handle  so  that  in  case 
the  oil  catches  fire  the 
cover  may  be  placed 
in  position,  thus  smoth- 
ering the  blaze  which 
might  endanger  the 
operator  and  property. 
Oils  with  a  high  flash 
test  may  be  used. 
Heavy  black  cylinder 
oil  is  supposed  to  have 
a  flash  test  of  725°  F. 
The  manufacturers  of 
FIG.  289.  some  special  temper- 

ing oils  claim  a  flash 

test  of  750°  F.  for  their  products  but  experience 
does  not  bear  out  these  claims.  In  ordinary  tem- 
pering it  is  seldom  necessary  to  exceed  630°  F.  and 
these  tempering  oils  are  perfectly  satisfactory  up  to 
and  above  this  point. 

When  an  oil  tempering  furnace  is  not  at  hand  and 
temperatures  ranging  from  430°  to  560°  F.  are  de- 


MISCELLANEOUS  WORK. 


249 


sired  the  following  alloys  may  be  used.  This  table 
was  compiled  by  Mr.  O.  M.  Becker  and  shows  the 
melting  points  of  the  various  alloys  of  lead  and  tin. 


Lead. 

Tin. 

Melting  Tem- 
perature. 
Degrees  F. 

Lead. 

Tin. 

Melting  Tem- 
perature. 
Degrees  F. 

14 

8 

42O 

24 

8 

480 

15 

8 

430 

28 

8 

490 

16 

8 

440 

38 

8 

510 

17 

8 

450 

60 

8 

530 

i8| 

8 

460 

96 

8 

550 

20 

8 

470 

2OO 

8 

560 

These  alloys  should  be  carefully  made  and  then  run 
into  small  strips  in  a  mold.  When  used,  bars 
having  the  desired  melting  point  should  be  placed  in  a 
melting  pot  heated  by  gas,  if  possible,  as  gas  flames 
are  more  easily  controlled  to  the  melting  point. 
Ths  insertion  of  the  tool  causes  the  metal  to  cool  and 
set  around  the  steel.  If  the  heating  is  carried  on 
gradually  the  tool  should  be  uniformly  heated  to  the 
desired  temperature  when  the  alloy  melts  clear  of 
the  tool.  While  this  gives  excellent  results  when 
properly  carried  on,  it  is  necessarily  costly  and  leaves 
room  for  unsatisfactory  results  in  any  but  a  skilled 
workman's  hands. 

For  temperature  above  700°  F.  a  bath  of  molten 
lead  is  used  with  good  results  if  the  lead  is  agitated 
frequently.  This  is  necessary  as  lead  forms  a  ' '  dead' ' 
bath,  that  is,  it  does  not  circulate  freely,  and  unless 
artificial  circulation  is  resorted  to,  the  pieces  will 
not  be  heated  uniformly  throughout.  The  tempera- 
ture of  the  bath  must  be  gauged  with  a  pyrometer 
as  shown  in  Fig.  275  and  the  pieces,  especially  if  large, 


250  FORGE-PRACTICE. 

allowed  to  remain  until  they  are  heated  to  the  tem- 
perature of  the  lead. 

The  workman  should  always  bear  in  mind  the  fact 
that  steel  hardened  at  the  proper  temperature  is  the 
strongest  possible.  If  this  temperature  is  exceeded, 
unnecessary  brittleness  results  which  necessitates 
drawing  the  temper  lower  than  it  should  be;  thus 
leaving  the  tool  softer  than  is  consistent  with  best 
results.  A  tool  hardened  at  the  proper  tempera- 
ture by  one  man,  and  drawn  to  400°  F.  gave  splendid 
results.  A  similar  tool  made  from  the  same  bar, 
hardened  by  another  man  had  to  be  drawn  to  460°  F. 
to  prevent  the  cutting  edge  from  flaking.  The  first 
tool  did  more  than  ten  times  the  amount  of  work, 
and  could  be  run  considerably  faster. 

There  are  several  forms  of  tempering  machines  on 
the  market.  Some  of  these,  especially  those  having 
revolving  trays  that  hold  the  pieces  of  work,  give 
very  good  results.  Such  a  furnace  is  shown  in  Fig. 
290.  It  must  be  borne  in  mind,  however',  that  the 
thermometer  provided  does  not  necessarily  register 
the  temperature  of  the  steel,  and,  therefore,  due 
allowance  must  be  made  for  this  difference.  For 
this  reason  this  machine  may  be  run  so  as  to  give 
good  results  where  a  given  size  and  kind  of  piece  is 
being  tempered  right  along,  and  it  is  for  this  condi- 
tion the  machine  is  made. 

While  red-hot  plates  are  commonly  used  in  tem- 
pering, and  answer  very  well  for  small  pieces  whose 
shape  is  such  that  sudden  expansion  at  some  portion 
does  no  harm,  there  are  many  classes  of  work  where 
their  use  is  not  to  be  advocated.  If  it  is  desirable 


MISCELLANEOUS  WORK. 


251 


FIG.  290. 


252 


FORGE-PRACTICE. 


to  use  a  plate  the  one  shown  in  Fig.  291  answers  the 
purpose  very  well.  The  end  farthest  away  from 
the  flame  should  be  the  starting  point  of  the  piece 
being  tempered  and  it  is  gradually  advanced  toward 
the  hot  portion.  By  keeping  the  plate  rilled  with 


Iron  Plate 


Tank 
of  Oil 


FIG.  291. 

pieces,  and  as  some  are  pushed  off  into  the  oil  and 
others  placed  on  the  cool  end,  a  considerable  amount 
of  work  may  be  done. 

Drawing  in  Sand. — A  long-handled  pan  as  shown  in 
Fig.  292  provides  a  means  of  uniformly  tempering  a 
great  many  small  pieces  in  a  relatively  short  time. 


FIG.  292. 

Nothing  but  clean  sand  should  be  used.  By  holding 
the  pan  over  an  open  fire  and  constantly  moving  it 
back  and  forth  uniform  results  may  be  obtained. 
Articles  having  sharp  edges  and  corners  should  not 
be  drawn  in  a  sand-shaking  pan. 


MISCELLANEOUS   WORK.  253 

Thermometer  Scales. — While  there  are  three  ther- 
mometer scales  in  general  use — namely  the  Fahren- 
heit (F.)>  Centigrade  (C).,  and  Reaumur  (R.) — but 
two  of  these  enter  into  calculations  in  heat-treating 
plants  in  the  United  States.  The  Fahrenheit  is  used 
in  English-speaking  countries,  and  the  Centigrade  in 
several  countries  on  the  continent,  and  to  a  consid- 
erable degree  in  scientific  work.  As  a  great  many  of 
the  writers  on  the  subject  under  consideration  state 
temperature  readings  according  to  the  Centigrade 
scale  and  most  men  employed  in  heat-treating  plants 
bave  heen  educated  to  think  according  to  the  Fahren- 
heit scale  it  seems  wise  to  give  the  comparative  table 
of  Fahrenheit  and  Centigrade  readings. 

The  freezing  point  of  fresh  water  is  marked  at  32 
degrees  on  the  Fahrenheit  scale,  and  at  o  on  the 
Centigrade,  while  the  boiling  point,  at  atmospheric 
pressure  is  marked  at  212  degrees  on  the  Fahrenheit 
and  at  100  degrees  on  the  Centigrade. 

The  table  on  p.  254  is  obtained  by  use  of  the  fol- 
lowing rule. 

To  convert  Fahrenheit  into  Centigrade  Readings: 
Subtract  32  from  Fahrenheit,  divide  remainder  by  9, 
and  multiply  by  5. 

EXAMPLE:    Change  430°  F.  to  C. 

432-32=398      398-^-9=44.22      44.22X5  =  221.1. 

Ans.  43o°F  =  22i.i°C. 

To  convert  Centigrade  into  Fahrenheit  Readings: 
Divide  by  5,  multiply  by  9  and  add  32. 

EXAMPLE:  Change  788°  C.  to  F. 
;38 -T- 5  =  157. 6     157.6X9  =  1418     1418-^32  =  1450  F. 

Ans.  788°  C,  =  1450°  F, 


254 


FORGE-PRACTICE. 


FAHRENHEIT  AND  CENTIGRADE  THERMOMETER  SCALES. 


F. 

c. 

F. 

C. 

F. 

C. 

-40 

-40 

190 

87.8 

1300 

704.0 

-35 

-37.2 

195 

90.6 

1350 

732.0 

-30 

-34-4 

20O 

93-3 

1400 

760.0 

-25 

-31-7 

205 

96.1 

1425 

773-9 

—20 

—28.9 

210 

98.9 

1450 

788.0 

-15 

-26.1 

212 

IOO.O 

1475 

801.6 

—  10 

-23-3 

215 

101.7 

1500 

816.0 

-  5 

—20.  6 

225 

107.2 

1550 

844.0 

o 

-17.8 

250 

121.  2 

1600 

872.0 

5 

-15 

300 

148.9 

1650 

899.0 

10 

—  12.2 

350 

176.7 

1700 

926.0 

15 

-  9-4 

400 

204.4 

1750 

954-0 

20 

-  6.7 

425 

218.3 

I800 

982.0 

25 

-  3-9 

430 

22  1.  I 

1850 

IOIO.O 

30 

—  i  I 

440 

226.7 

1900 

1038.0 

32 

0.0 

450 

232.2 

1950 

1065.5 

35 

i-7 

460 

237.8 

2OOO 

1093.0 

40 

4-4  . 

470 

243-3 

2050 

II2I  .O 

45 

7-2 

480 

248.9 

2IOO 

II49-0 

50 

10.  0 

490 

254-9 

2150 

II76.5 

55 

12.8 

500 

260.O 

22OO 

I2O4.O 

60 

15.6 

510 

265.6 

2250 

1232.0 

65 

18.3 

520 

27I.I 

2300 

1260  o 

70 

21.  1 

530 

276.7 

2350 

1287.5 

75 

23-9 

540 

282.2 

240O 

I3I5.5 

80 

26.7 

550 

287.8 

2450 

1343  0 

85 

29.4 

560 

293  3 

2500 

1371.0 

90 

32.2 

570 

298.9 

2550 

1399.0 

95 

35-0 

580 

304-4 

2600 

1426.5 

100 

37-8 

590 

310.0 

2650 

H55-0 

105 

40.6 

600 

3I5-6 

2700 

1483.0 

no 

43-3 

610 

321.1 

2750 

1510.0 

115 

46.1 

620 

326.7 

2800 

J537-5 

I2O 

48.9 

630 

332.2 

2850 

1565  o 

125 

5i-7 

650 

343-3 

29OO 

1593  o 

130 

54-4 

700 

37I-I 

2950 

1621  .0 

135 

57-2 

750 

398.9 

3000 

1648.5 

140 

60.0 

800 

426.7 

3050 

1676.0 

145 

62.8 

850 

454-4 

3100 

1705.0 

150 

6s.  6 

900 

482.2 

3150 

1732.0 

155 

68.3 

950 

510.0 

3200 

1760.0 

160 

71.1 

IOOO 

537-8 

3300 

1815.6 

165 

73-9 

1050 

565-5 

3400 

1871.1 

170 

76.7 

IIOO 

593-0 

3500 

1926.7 

175 

79  4 

1150 

621  .0 

1  80 

82.2 

I2OO  ' 

648.5 

185 

85.0 

1250 

676.5 

MISCELLANEOUS   WORK.  255 

Toughening. — While  full  annealing  relieves  strains 
in  steel  and  gives  the  maximum  toughness,  it  does 
not  always  give  the  necessary  degree  of  stiffness. 
In  order  to  produce  the  toughness  and  stiffness  nec- 
essary many  different  treatments  are  resorted  to. 
The  exact  treatment  necessary  to  produce  desired 
results  depends  on  the  composition  of  the  steel  and 
the  strains  it  is  to  receive  when  in  use. 

Large,  heavy  pieces  are  many  times  heated  to 
the  refining  heat  and  partially  quenched  in  water, 
after  which  they  are  allowed  to  cool  in  the  air.  The 
internal  heat  returns  to  the  surface  and  toughens 
the  external  portion.  Smaller  pieces  are  partially 
or  wholly  cooled  in  oil  and  then  reheated  to  give  the 
desired  result.  The  amount  of  heat  given  when 
reheating  varies  from  500°  to  1000°  F. 

In  other  cases  the  pieces  are  brought  to  the  refin- 
ing temperature  and  thrown  onto  a  floor  of  dry  sand 
in  a  room  where  a  definite  temperature  can  be  main- 
tained. Where  this  does  not  produce  the  necessary 
degree  of  stiffness  a  gentle  stream  of  warm  air  may 
be  blown  across  the  pieces.  Better  results  follow 
this  method  when  the  articles  are  placed  on  wire 
racks  so  that  the  air  may  have  free  access  to  all 
parts. 

Large  forgings  are  heated  red  hot  and  allowed  to 
cool  by  piling  in  heaps  and  cooled  where  no  draft 
of  air  can  strike  them.  It  is  obvious  that  such 
treatment  will  result  in  an  unevenly  cooled  surface 
especially  if  the  steel  contains  more  than  0.40  per 
cent  carbon,  as  the  more  exposed  portions  will  cool 
more  quickly  than  the  others.  However,  if  the 


256  FORGE-PRACTICE. 

results  are  commercially  satisfactory,  the  method 
commends  itself  on  account  of  the  comparatively  low 
cost. 

Where  large  pieces  are  toughened  by  quenching  in 
oil,  it  is  necessary,  in  order  to  get  uniformly  good 
results,  to  heat  to  a  given  pre-determined  temperature, 
quench  in  oil  for  a  given  number  of  seconds,  and 
then  allow  the  pieces  to  cool  in  the  air.  To  insure 
satisfactory  results  by  this  method  temperatures,  and 
exposure  to  the  bath,  must  be  determined  by  experi- 
ment, and  followed  absolutely. 

In  all  shop  processes  it  must  be  borne  in  mind  that 
methods  commercially  possible  must  be  followed, 
provided  they  produce  results  that  are  commer- 
cially satisfactory. 

Hardening  and  Toughening. — In  the  case  of  the  pipe- 
wrench  jaw  shown  in  Fig.  293 ,  it  is  necessary  to  harden 
the  portion  (a),  Fig.  294,  containing  the  teeth,  and 
to  toughen  the  rib  (b).  This  is  accomplished  by  care- 
fully heating  to  the  proper  temperature,  which  in  the 
case  of  steel  of  0.70  per  cent  carbon  is  about  1475°  F., 
then  quenching  the  teeth  by  holding  under  a  stream 
of  water  as  shown  in  Fig.  294.  When  the  red  has 
disappeared  from  the  teeth  the  piece  may  be  im- 
mersed in  oil  and  allowed  to  remain  until  cold. 

A  method  of  toughening  practiced  in  some  places 
consists  in  heating  to  a  low  red  and  burying  in  damp 
sand,  after  which  they  may  be  reheated  to  a  tempera- 
ture that  insures  the  desired  strength  and  tough- 
ness. While  this  method  gives  satisfactory  results 
on  certain  kinds  of  work,  it  is  doubtful  if  it  produces 
as  great  a  degree  of  strength  and  toughness  as 


MISCELLANEOUS  WORK. 


257 


though  they  were  quenched  in  oil  and  then  tem- 
pered. 

Articles  that  have  heavy  and  light  sections  ad- 
joining each  other  and  where  both  must  be  hardened 
require  special  care  when  quenched  or  the  unequal 
contraction,  incident  to  the  difference  in  size,  may 


FIG.  293. 


FIG.  294. 


result  in  cracks  or  breakage.  The  T  slot  cutter 
shown  in  Fig.  295  is  an  example  that  answers  well  as 
an  illustration.  It  is  necessary  to  harden,  not  only 
the  cutting  portion,  but  also  the  neck  (b)  in  order  to 
give  it  the  necessary  stiffness  and  to  prevent  its 
roughing  up  when  in  use. 


258  FORGE-PRACTICE. 

To  prevent  the  tool  cracking  when  quenched  it  is 
advisable  to  wind  soft  iron  around  the  neck  at  a  and 
close  up  to  the  body.  If  small  wire  is  used  it  is 
necessary  to  pass  the  wire  several  times  around  the 
piece.  As  the  wire  is  red  hot  at  the  time  of  quenching 
sudden  contraction  at  this  point  is  avoided. 

At  times  tools  of  this  kind  have  extremely  large 
center  holes  in  the  end  that  is  to  be  hardened.  Such 
holes  should  be  filled  with  fire  clay  dough  before  the 
pieces  are  placed  in  the  fire.  This  precaution  should 


FIG.  295. 

always  be  observed  except  in  the  case  of  tools  that 
are  to  run  on  centers. 

The  Magnet  in  Hardening. — When  steel  is  heated  it 
retains  its  ability  to  attract  the  magnetic  needle,  or 
a  magnet,  to  what  is  known  as  the  decalescence 
point.  When  a  piece  of  steel  is  heated  in  a  fire  that 
is  hotter  than  the  temperature  to  which  the  steel 
should  be  brought  the  metal  absorbs  heat  fairly 
constantly  until  a  certain  temperature  is  reached, 
when  there  appears  to  be  a  lag  in  the  process;  this 
is  known  as  the  decalescence  point.  At  this  tempera- 
ture the  steel  will  neither  be  affected  by  the  magnet, 
nor  will  it  attract  the  compass  needle.  Care  should 


MISCELLANEOUS   WORK.  2  59 

be  exercised  that  the  tongs,  or  other  holder  ordinarily 
used  is  not  present  when  the  test  is  made,  or  the 
operator  may  be  deceived.  This  same  piece  of  steel  if 
heated  to  a  high  temperature  and  allowed  to  cool, 
will,  when  at  a  certain  temperature,  show  a  lag  and 
will,  apparently,  grow  hotter  even  when  cooling  in 
the  air.  This  is  known  as  the  recalescence  point.  This 
phenomenon  takes  place  at  a  temperature  ranging 
from  85°  to  215°  F.  lower  than  the  decalescence 
point.  Steel  must  be  heated  to  the  decalescence 
point  in  order  to  harden,  and  it  must  be  quenched 
before  it  drops  to  the  recalescence  point  or  it  will 
not  harden.  Steel  should  be  hardened  at  the  highest 
temperature  to  which  it  should  be  heated,  and  on  a 
rising  heat,  never  on  a  descending  heat. 

The  use  of  the  magnet  is  to  be  advocated,  as  the 
eye  is  not  always  to  be  relied  upon.  A  man's  bodily 
condition  has  a  great  deal  to  do  with  his  ability  to 
discern  heats,  and  the  lighting  conditions  many  times 
cause  one  to  be  deceived  even  when  the  eye,  under 
proper  conditions,  would  give  accurate  results.  As  a 
man  grows  older,  his  eyes  change  and  unless  he  has 
some  standard  to  check  up  by  he  fails  to  discern 
heats,  and  is  rated  as  a  ''back  number"  at  a  time 
when  his  long  experience  should  make  him  invaluable. 
The  trouble  arises  from  the  fact  that  the  man  will 
not  acknowledge  to  himself  that  his  eyes  are  changing 
and  instead  of  realizing  this  and  frequently  checking 
up  by  means  of  a  magnet,  in  the  absence  of  a  pyrom- 
eter, he  goes  on  until  it  is  apparent  to  everyone  that 
his  days  of  usefulness  are  past.  And  many  times 
this  is  due  to  the  fact  that  he  did  not  "check"  him- 


260  FORGE-PRACTICE. 

self  frequently  rather  than  to  admit  a  change  of  eye- 
sight, or  ability. 

A  very  successful  hardener  who  is  working  in  a 
factory  where  every  appliance  for  producing  good 
results  is  employed  "checks  up"  ten  to  fifteen  times 
a  day  with  a  magnet.  He  says  he  is  not  sure  of  his 
heats  when  he  returns  to  his  fire  after  leaving  and 
going  where  the  light  conditions  are  different.  Most 
workmen  are  not  aware  of  the  harmful  effects  of  a 
slight  variation  in  temperature  on  certain  classes  of 
tools.  The  fact  that  a  tool  hardened  without 
cracking  or  undue  distortion  is  no  proof  that  it  is  in 
the  best  possible  condition  for  the  use  it  is  intended 
for. 

While  the  decalescence  point  is  not  in  all  cases 
the  most  suitable  temperature  to  be  employed  in 
hardening,  it  is  a  safe  guide  as  to  the  lowest  point  at 
which  the  steel  will  harden  properly.  The  exact 
amount  of  additional  heat  necessary  to  produce  some 
desired  result  necessitates  a  knowledge  gained  by 
experience,  but  the  inexperienced  man  can  gain  this 
knowledge  by  diligent  study  and  intelligently  con- 
ducted experiments. 

Springing. — Springing  many  times  results  when 
pieces  are  hardened.  This  may  or  may  not  be  the 
hardener's  fault.  The  careful  man  will  use  every 
precaution  possible  to  prevent  distortion,  but  the 
cause  of  the  trouble  may  not  be  anything  that  he  has 
done,  or  anything  he  could  counteract  had  he  known 
of  it  before  hardening.  As  previously  stated  the 
piece  of  steel  may  have  been  straightened  cold,  or 
the  piece  may  have  been  machined  with  a  dull  cut- 


MISCELLANEOUS  WORK.  26 1 

ting  tool  which  set  up  strains  in  the  steel.  The 
opening  of  a  blanking  die  may  have  been  worked  out 
a  trifle  too  large  and  then  pened  in  cold  in  which 
case  distortion  might  result  when  the  die  was  hard- 
ened. Long,  slender  pieces  should  never  be  placed 
in  a  furnace,  in  such  a  manner  that  they  could  bend 
from  the  weight  of  the  metal  when  red  hot.  If  pos- 
sible, heat  in  a  furnace  of  the  design  shown  in  Fig.  268 ; 
if  this  is  not  possible  place  in  a  tube  and  turn  fre- 
quently. When  it  has  reached  the  proper  hardening 
temperature  remove  the  tube  from  the  furnace  and 
stand  in  an  upright  position  before  taking  the  piece 
from  the  tube.  As  the  piece  is  lifted  vertically  the 
tendency  to  spring  is  much  less  than  if  it  was 
heated  in  a  horizontal  position  on  the  floor  of  the 
furnace,  drawn  out  and  then  brought  to  a  vertical 
position  preparatory  to  dipping  in  the  bath. 

Pieces  of  this  kind  should  be  lowered  into  the  bath 
in  as  nearly  a  perfectly  vertical  position  as  possible 
to  prevent  one  side  cooling  faster  than  the  other. 
Pieces  of  the  description  under  consideration  give 
best  results  when  pack  hardened  and  quenched  in 
oil.  However,  if  the  ordinary  fire  and  water  method 
must  be  used,  have  the  contents  of  the  bath  at  a 
temperature  of  from  80°  to  90°  F. 

Straightening. — If  extreme  care  in  heating  and 
quenching  is  exercised,  springing  or  other  distortion 
will  be  reduced  to  the  minimum.  However,  pieces 
will  some  times  go  out  of  true  and  must  be  straight- 
ened, by  first  heating  the  articles  and  then  applying 
pressure.  This  pressure  should  be  gradual  and 
should  be  kept  up  until  the  piece  is  cooled.  If  the 


262  FORGE-PRACTICE. 

article  is  not  too  large  in  cross-section  and  has  centers 
in  its  ends  it  may  be  placed  between  the  centers  of  a 
lathe,  then  heated  by  means  of  a  Bunsen  burner,  gas 
jet,  or  spirit  lamp,  until  lard  oil  applied  to  the  sur- 
face commences  to  smoke,  after  which  pressure  may 
be  applied  to  the  convex  side  by  means  of  a  tool 
shank  held  in  the  tool  post.  The  pressure  should  be 
sufficient  to  spring  the  article  slightly  in  the  opposite 
direction,  when  it  may  be  cooled  by  applying  wet 
cloths  or  waste  uniformly  to  all  parts  of  the  surface; 
or  it  may  be  left  between  the  centers  until  cooled  by 
the  air.  If  it  is  found  to  be  sprung  when  tested  it 
should  be  reheated  and  the  above  operation  repeated. 
Do  not  attempt  to  spring  hardened  steel  without 
heating,  no  matter  how  many  times  it  has  pre- 
viously been  heated.  Hardened  steel  cannot  be 
bent  when  cold  by  a  man  of  ordinary  experience  with 
any  degree  of  safety.  Slender  pieces  are  sometimes 
straightened  after  the  temper  is  drawn,  and  when 
cold,  by  pening,  by  men  experienced  in  this  work, 
but  this  practice  is  not  to  be  advocated. 

Pieces  that  have  no  centers  can  be  straightened 
in  a  screw  press.  It  is  necessary  to  support  them  on 
blocks  located  a  convenient  distance  apart,  and 
applying  pressure  between  them  after  heating. 

Changes  in  Length. — Steel  of  ordinary  composition 
has  a  tendency  to  change  in  length  when  hardened. 
This  can  be  overcome,  to  a  degree,  by  annealing  at  a 
temperature  somewhat  higher  than  hardening  heats 
after  the  pieces  are  rough  machined.  Steel  contain- 
ing certain  elements  has  less  tendency  to  change  than 
others  and  for  this  reason  is  advocated  for  use  in  mak- 


MISCELLANEOUS   WORK.  263 

ing  taps.  Taps  that  are  annealed  as  described  above 
and  then  pack  hardened  have  little  tendency  to  a 
change  of  pitch.  Consequently  this  method  is  ad- 
vocated whenever  possible  for  this  class  of  tool, 
particularly  where  change  of  pitch  is  fatal  to  the  tool. 

Value  of  Experiments. — It  is  advisable,  at  times,  to 
vary  the  treatment  given  a  tool  and  then  closely 
watch  results  when  it  is  set  to  work.  This  does  not 
apply  where  satisfactory  results  are  being  obtained 
by  some  method  that  has  been  found  to  work  all 
right;  but,  in  the  case  of  a  new  kind  of  tool;  or, 
where  a  tool  is  being  used  on  stock  entirely  different 
from  that  used  before. 

The  character  of  the  work  a  tool  is  to  perform, 
and  the  composition  of  the  steel  from  which  it  is 
made  must  be  known  in  order  that  the  right  treat- 
ment may  be  given  it.  No  experienced  hardener, 
or  technical  expert,  for  that  matter,  can  always  tell 
offhand  the  best  treatment  to  give  a  tool  unless  the 
conditions  mentioned  are  known.  He  can  in  all 
probability  give  a  safe  course  to  pursue  in  treating  it, 
but  this  should  not  be  the  prime  essential  to  be  con- 
sidered, regardless  of  the  capability  of  the  tool  to  do 
the  maximum  amount  of  work  in  a  given  time.  It 
is,  of  course,  necessary  to  keep  an  accurate  account 
of  the  cost  of  the  various  operations  performed  in  a 
heat-treating  department,  the  same  as  in  any  other 
part  of  the  factory,  but  because  a  certain  operation 
cost  a  given  sum  to  perform  at  some  previous  time  is 
no  reason  that  a  treatment  costing  several  times  as 
much  is  not  advisable  if  results  in  the  use  of  the  tool 
warrant  the  added  expense. 


264  FORGE-PRACTICE. 

If  the  material  from  which  the  tool  is  made  plus 
the  cost  in  the  tool  room  of  getting  it  ready  for  the 
hardener  aggregates  $50  it  is  poor  policy  to  pursue 
a  method  in  hardening  that  costs  but  50  cents, 
when  a  method  that  involves  an  expense  of  $5  would 
put  the  tool  in  condition  to  produce  many  times  more 
work  before  it  was  scrapped.  Yet  this  "penny  wise, 
pound  foolish"  system  is  still  adhered  to  in  some 
shops.  The  expense  account  should  rather  be  kept 
with  the  tool;  its  cost  of  production  and  mainte- 
nance, as  against  the  amount  of  work  produced  by  it, 
etc. 

The  entrance  of  technically  educated  men  into 
factories  has  done  a  great  deal  toward  eliminating 
many  of  the  foolish  practices  in  some  plants.  The 
technically  educated  man,  however,  should  "serve 
his  term"  in  the  heat-treating  room  and  the  pro- 
duction departments  getting  familiar  with  operations 
and  requirements  before  he  is  permanently  located  in 
the  chemical  laboratory  and  allowed  to  dictate  the 
course  and  methods  to  be  pursued  in  the  heat- 
treating  department,  as  otherwise  a  condition  less 
desirable  than  that  occasioned  by<  "hit  or  miss" 
methods  may,  and  probably  will,  result. 

So  far  as  possible  each  class  of  tool  that  is  heat 
treated  should  receive  personal  consideration.  Its 
chemical  analysis,  design,  material  it  is  to  cut, 
amount  of  work  it  is  to  produce  in  a  given  time,  and 
conditions  under  which  it  is  to  work  should  be  taken 
into  account  in  determining  the  treatment  it  should 
receive.  At  times  a  slight  variation  in  temperature 
or  time  exposure  will  work  wonders.  A  certain  class 


MISCELLANEOUS  WORK.  265 

of  tool  that  had  been  hardened  from  a  temperature 
of  1400°  F.  was  heated  to  1430°  F.  and  an  increase 
of  50  per  cent  in  the  amount  of  work  produced  by 
the  tool  was  obtained.  A  tool  made  from  a  well- 
known  alloy  steel  was  hardened  at  1375°  F.  accord- 
ing to  instructions  on  the  bar,  with  fair  results.  On 
the  advice  of  a  representative  of  the  concern  from 
whom  the  steel  was  purchased,  one  of  the  tools  was 
hardened  at  1500°  F.  and  results  way  beyond  any- 
thing thought  of  were  obtained.  The  writer  does  not 
wish  to  be  understood  as  advocating  high  tempera- 
tures when  heating  steel  for  any  of  the  heat-treating 
processes,  but  in  the  case  just  cited  the  heat  men- 
tioned was  needed  to  bring  out  certain  qualities  in 
the  steel. 

At  times  a  trifling  drop  in  temperature  will  work 
wonders  especially  in  the  case  of  cutting  tools  having 
projecting  cutting  teeth.  In  some  cases  a  micro- 
scopical examination  of  the  surfaces  of  the  fracture  in 
the  body  of  the  tool  might  show  that  the  steel  was 
underheated,  while  a  similar  examination  of  a 
broken  tooth  would  indicate  correct  heating  and  yet 
both  body  and  teeth  might  have  been  at  the  same 
temperature  so  far  as  is  humanly  possible  to  heat 
such  pieces.  In  the  case  just  considered  the  cutting 
teeth  are  the  portions  to  be  considered,  consequently 
the  temperature  employed  must  be  one  that  gives 
best  results  here.  This  case  emphasizes  the  repeated 
statements  of  writers  dealing  with  the  subject  under 
consideration  that  variations  of  temperature  are 
necessary  for  pieces  of  different  sizes  and  shapes 
made  from  steel  of  the  same  composition. 


266  FORGE-PRACTICE. 

Annealing. — The  term  annealing,  as  generally 
understood,  means  the  softening  of  materials  so  that 
they  will  be  workable.  At  the  present  time,  and  by 
those  engaged  in  the  heat  treating  of  steel,  the  word 
has  a  much  broader  meaning.  Crucible  tool  steel  as 
it  leaves  the  finish  hammer,  or  rolls  in  the  steel  mill  is 
quite  hard  and  filled  with  strains.  The  condition  of 
hardness  renders  machining  difficult,  or  impossible. 
To  overcome  this  difficulty,  and  to  remove  the  strains, 
the  steel  is  heated  to  a  uniform  red  and  allowed  to 
cool  slowly. 

The  exact  temperature  to  which  a  piece  of  steel 
should  be  heated  for  annealing  depends  on  the  crit- 
ical temperature  of  the  steel.  This  temperature 
varies  somewhat  and  depends  on  the  composition  of 
the  steel,  on  the  size,  and  on  the  subsequent  treat- 
ment it  is  to  receive.  However,  it  is  generally 
advisable  to  bring  the  steel  to  a  somewhat  higher 
heat  than  it  is  to  receive  when  hardened.  In  this 
way  it  is  reasonably  certain  that  strains  that  would 
otherwise  be  relieved  by  the  hardening  heat,  will 
be  eliminated  in  the  annealing.  The  exact  increase 
in  temperature  above  the  critical  point  cannot  be 
stated  arbitrarily,  but  in  ordinary  practice  is  about 
50°  F.  Where  special  objects  are  to  be  attained, 
this  temperature  is  sometimes  exceeded.  However, 
very  high  annealing  heats  are  liable  to  produce  a 
product  that  is  difficult  to  machine,  for  while  it  may 
appear  to  be  soft  under  a  file  test,  tools  will  dull 
rapidly  when  cutting  it. 

Where  it  is  necessary  to  heat  pieces  much  more 
than   50°  F.   above  the  refining  heat,  in  order  to 


MISCELLANEOUS  WORK.  267 

release  strains  that  may  manifest  themselves  when 
hardening,  and  where  the  pieces  are  to  be  machined, 
it  is,  at  times,  advisable  to  resort  to  ' '  double  anneal- 
ing." That  is,  first,  heat  to  the  higher  temperature 
and  allow  them  to  cool,  then  heat  to  a  few  degrees 
above  the  refining  heat  and  allow  them  to  cool  the 
second  time,  thus  doing  away  with  the  crystalline 
grain  incident  to  the  high  heat. 

In  any  of  the  operations  involved  in  the  heat 
treatment  of  steel  it  is  always  advisable  to  heat  as 
rapidly  as  possible  and  yet  heat  uniformly.  On  the 
other  hand  steel  should  not  be  heated  too  rapidly 
as  ununiform  heats  may  set  up  strains  that  are  more 
serious  than  those  we  are  attempting  to  remove  by 
the  annealing  process.  If  a  large  die  block,  rect- 
angular in  shape,  is  placed  in  the  furnace  and  heated 
there  is  a  tendency,  unless  care  is  exercised,  to  over- 
heat the  corners  and  edges  before  the  center  of  the 
block  has  reached  the  proper  temperature. 

A  piece  of  steel  always  shows  the  effect  of  the  last 
heat  it  receives,  and  each  portion  of  every  piece 
shows  the  effect  of  the  heat  it  receives,  as  a  result, 
an  overheated  piece,  if  it  is  ununiformly  overheated, 
shows  an  ununiform  granular  condition  that  varies 
throughout  accordingly  as  the  piece  was  heated. 
This  granular  condition  indicates  that  the  steel  has 
been  weakened,  and  if  the  weakening  is  not  uniform 
throughout  the  piece  it  is  in  poor  condition  to  be 
hardened,  or  to  receive  excessive  strains  of  any  kind. 
It  is  a  mistake  to  keep  a  piece  of  carbon  tool-steel 
red  hot  any  longer  than  is  necessary  after  it  is  uni- 
formly heated  throughout,  as  prolonged  heats,  when 


268  FORGE-PRACTICE. 

annealing,  even  when  the  steel  is  not  overheated, 
tends  to  weaken  it,  and  to  produce  a  condition  that 
renders  machining  with  cutting  tools  difficult. 

A  mistake  often  made  in  annealing  is  to  heat  the 
piece  too  hot  and  to  hold  it  at  this  heat  for  too  long  a 
time ;  then  when  an  attempt  is  made  to  machine  it, 
difficulty  is  experienced.  The  piece  is  returned  to 
the  heat-treating  department  and  it  is  heated  hotter 
and  kept  hot  longer  than  before,  with  the  result  that 
each  time  it  is  treated  conditions  are  found  worse. 

The  writer  recalls  a  die  block,  on  the  face  of  which 
an  impression  was  to  be  made  by  engraving.  After 
repeated  attempts  to  anneal  the  steel,  the  block  was 
sent  to  our  plant.  An  examination  of  the  grain  of  a 
piece  cut  from  the  block  showed  it  to  be  extremely 
granular.  While  the  steel  showed  soft  under  file 
test,  it  appeared  to  be  extremely  weak  when  broken, 
indicating  excessive  and  long-continued  heats.  The 
block  was  placed  in  the  furnace  and  carefully  heated 
to  the  proper  temperature,  making  sure  that  the 
temperature  was  uniform  throughout.  It  was  then 
removed  from  the  furnace  and  buried  in  ashes.  The 
ashes  that  came  in  contact  with  the  steel  were  heated 
to  a  temperature  of  about  1000°  F.  while  the  balance 
of  the  ashes  were  not  heated,  but  were  perfectly  dry. 
When  the  piece  was  cool  it  was  found  to  be  in  excel- 
lent condition  for  machining. 

A  method  of  annealing,  where  but  a  few  compara- 
tively small  pieces  are  to  be  treated,  consists  in 
heating  to  a  red  and  burying  in  ashes,  lime  or  asbes- 
tos and  allowing  them  to  remain  until  cool.  If  the 
pieces  are  properly  heated,  and  the  material  they  are 


MISCELLANEOUS  WORK.  269 

buried  in  is  warm  and  dry  good  results  generally 
follow.  Burying  red-hot  steel  in  cold  or  damp  ma- 
terials has  a  tendency  to  partially  harden  it.  A 
method  practiced  by  some  consists  in  heating  a  piece 
of  scrap  iron  or  steel  to  a  red  and  burying  in  ashes, 
lime  or  whatever  is  used  and  allowing  it  to  remain 
there  until  the  piece  to  be  annealed  is  properly  heated, 
when  it  is  removed  and  the  steel  buried  in  the  heated 
material. 

Box  Annealing. — Undoubtedly  hundreds  of  thou- 
sands of  dollars  worth  of  steel  is  rendered  unfit  for 
use  each  year  by  this  method  of  annealing ;  but,  it  is 
not  wise  to  condemn  a  method  because  it  is  not 
properly  done. 

As  previously  stated,  the  one  who  is  responsible 
for  the  heat  treatment  of  steel  should  understand 
steel.  If  a  batch  of  small  forgings  made  from  a 
comparatively  low  carbon  steel  is  to  be  annealed, 
it  might  be  perfectly  proper  to  use  a  method  that 
might  prove  very  unsatisfactory  if  the  same  pieces 
were  made  from  medium  or  high  carbon  stock. 

It  is  poor  practice  to  anneal  a  large  box  of  small 
pieces  made  from  high  carbon  steel,  as  the  pieces 
located  in  various  parts  of  the  box  would  remain  red 
hot  for  different  lengths  of  time.  As  a  result  the 
action  of  the  process  would  tend  to  produce  a  product 
that  was  not  uniform  and  difficulty  would  be  experi- 
enced when  they  were  machined. 

Small  pieces  should  be  packed  in  small  boxes,  and 
the  boxes  removed  from  the  furnace  as  soon  as  the 
contents  are  uniformly  heated  to  the  proper  tem- 
perature. It  is  not  to  be  understood  that  small 


270 


FORGE-PRACTICE. 


pieces  made  from  low  carbon  steel  would  be  so  easily 
injured  if  packed  in  large  boxes,  as  the  lower  the 
carbon  the  less  sensitive  the  steel  is  to  the  injurious 
effects  of  long  heats.  Trouble  is  experienced  here  at 
times  when  the  workman  is  told.  "These  pieces 
are  made  from  machine  steel,"  as  the  so-called  ma- 
chine steel  may  contain  a  high  percentage  of  carbon, 
and  the  effect  of  long-continued  heats  is  just  as 
apparent  as  though  the  stock  was  crucible  tool  steel 
of  the  same  carbon  content. 

Test 
Wires 


FIG.  296. 

It  is  a  good  plan  to  use  test  wires  as  shown  in 
Fig.  296  in  order  to  determine  when  the  pieces  at  the 
center  of  the  box  are  heated  to  the  desired  tempera- 
ture. Several  \"  holes  are  drilled  through  the  box 
covers  as  shown,  and  •£%"  wires  are  thrust  down 
through  the  packing  material  to  the  bottom  of  the 
box.  When  the  work  has  been  exposed  to  the  action 
of  the  heat  for  a  time  one  of  the  wires  may  be  drawn 
by  means  of  long  tongs  and  its  condition  noted.  In 
a  short  time  a  second  wire  may  be  removed  and  this 
continued  until  one  is  drawn  that  shows  the  proper 
color. 


MISCELLANEOUS   WORK.  271 

The  pieces  should  be  arranged  in  the  box  so  that 
they  will  not  be  within  an  inch  of  the  walls  at  any 
point.  The  packing  material  used  may  be  pul- 
verized charcoal,  coal  dust,  lime,  asbestos,  sand 
or  any  material  that  will  answer  the  purpose  and  yet 
have  no  undesirable  effect  on  the  steel. 

Some  writers  claim  that  a  furnace  heated  to  a 
given  temperature  will  heat  a  piece  of  a  given  size 
and  shape  to  a  definite  temperature  in  a  given  time. 
The  writer's  experience  does  not  coincide  with  this 
claim.  There  are  a  number  of  conditions  that  have 
a  decided  effect  on  the  exact  length  of  time  it  takes 
steel  to  absorb  heat.  This  is  especially  true  of  work 
packed  in  boxes.  It  is  wise  to  have  records  showing 
the  approximate  time  required  to  heat  given 
sized  pieces  and  boxes  to  certain  temperatures, 
but  such  records  should  not  be  considered  as 
absolute. 

It  sometimes  happens  that  an  entirely  unlooked- 
for  and  undesired  result  is  obtained  by  packing  the 
steel  for  annealing  in  material  not  suited  for  the  pur- 
pose. Where  low  carbon  steel  pieces  are  to  be 
annealed,  and  it  is  not  desirable  to  increase  the  car- 
bon content,  a  packing  material  that  will  not  impart 
carbon  should  be  used.  A  batch  of  forgings  were 
made  for  a  manufacturer  of  guns  which  were  to  be 
machined-  and  then  bent  to  an  irregular  form.  As  it 
was  necessary  to  anneal  them  to  put  them  in  con- 
dition for  machining  they  were  packed  in  boxes  and 
no  thought  given  to  the  action  of  the  packing  ma- 
terial. The  material  used  was  wood  charcoal. 
When  machined  they  cut  nicely,  but  when  an 


272  FORGE-PRACTICE. 

attempt  was  made  to  bend  them  to  a  finished  form, 
they  broke.  Investigation  showed  that  carbon  was 
charged  into  them  in  the  annealing  process.  In 
order  to  save  the  pieces  and  make  bending  possible 
they  were  re-annealed  in  forge  scale  (oxide  of  iron), 
which  contains  no  carbon,  and  which  absorbed  the 
excess  carbon  from  the  forgings  making  cold  bending 
possible. 

At  times  high-carbon  steel  pieces  are  packed  in 
some  material  that  draws  the  carbon  out  and  leaves 
the  steel  unfit  for  use.  This  may  be  rectified  by  re- 
annealing  in  charred  leather  or  charcoal,  making 
sure  that  the  time  exposure  for  recharging  is  about 
the  same  as  when  the  carbon  was  extracted. 

If  it  is  desirable  to  use  a  high  carbon  steel  and 
none  is  at  hand  the  finished  tool  may  be  packed  in 
charred  leather  and  run  at  a  temperature  of  1400°  to 
1450°  F.  from  two  to  four  hours,  after  which  it  may 
be  allowed  to  cool  and  then  hardened. 

The  operator  should  understand  that  while  certain 
materials  are  very  desirable  as  packing  materials 
when  annealing  certain  pieces  their  use  is  to  be  dis- 
couraged for  other  purposes.  Tool  steel  to  be  used 
for  most  cutting  tools  can  be  satisfactorily  annealed 
if  packed  in  charcoal;  yet  tools  to  be  subjected  to 
certain  strains  where  an  increase  of  carbon  is  unde- 
sirable should  not  be  exposed  to  charcoal,  or  any 
other  carburizer.  They  should  not  be  heated  in 
contact  with  decarburizers  or  the  carbon  content 
at  the  surface  will  be  lowered.  When  in  doubt  as 
to  the  desirable  material  to  be  used  it  is  best  to 
select  a  neutral.  The  writer  has  in  such  cases  used, 


MISCELLANEOUS  WORK.  273 

with  good  results,  finely  sifted  coal  ashes,  or  dry  fire 
clay. 

When  one  understands  the  action  of  different 
packing  materials  it  is  possible  many  times  to  treat 
a  stock  not  exactly  suited  to  a  certain  purpose  in 
such  a  manner  as  to  add  to  it,  or  take  from  it  carbon, 
and  accomplish  the  desired  result. 

Articles  made  from  sheet  steel,  or  which  are  light 
in  cross-section,  if  made  from  medium  or  high- 
carbon  steel  seldom  show  good  results  if  box  an- 
nealed. Take,  for  instance,  jack-knife  blades, 
springs,  etc.  Such  pieces,  especially  if  they  are  to 
be  machined,  are  best  annealed  by  heating  in  a  fur- 
nace where  no  direct  flame  can  strike  them,  removing 
as  soon  as  uniformly  heated  to  the  proper  tempera- 
ture and  placing  in  a  box,  in  the  bottom  of  which  is  a 
quantity  of  hot  ashes.  As  these  pieces  are  con- 
stantly added  they  cool  very  slowly.  When  the 
box  is  nearly  full  the  balance  of  space  may  be  filled 
with  hot  ashes.  The  blades  do  not  remain  red  hot 
very  long,  but  cool  very  slowly  from  about  1000°  F. 
.The  same  pieces  if  box  annealed  would  have  a  coarse 
structure  and  would  give  considerable  trouble  when 
drilled,  or  machined  by  any  method. 

Water  Annealing. — The  opinions  of  writers  and 
hardeners  differ  widely  as  to  the  value  of  water 
annealing.  The  opinion,  as  generally  given,  is  that 
it  is  a  good  practice  to  let  alone.  There  are  times 
when  it  is  necessary  to  anneal  a  piece  of  steel  as 
quickly  as  possible,  and  if  the  shape  of  the  piece  is 
such  that  uniform  cooling  down  to  the  point  where  the 
red  disappears  from  the  steel  when  the  piece  is  held 


274  FORGE-PRACTICE. 

in  a  dark  place  is  possible,  fairly  good  results  follow 
if  it  is  immediately  plunged  in  water,  oil,  or  soapy 
water. 

There  are  times  when  it  does  not  seem  possible 
to  anneal  steel  by  the  regular  methods  so  that  it  will 
be  in  the  desired  condition,  and  where  water  annealing 
(so-called)  will  give  satisfaction.  The  writer  recalls 
some  tap  blanks  that  could  not  be  threaded  in  the 
lathe  without  "tearing,"  that  is,  the  stock  would  tear 
out  on  the  sides  of  the  thread.  The  steel  appeared 
to  be  weakened  by  the  annealing  as  there  was  not 
sufficient  strength  to  hold  it  together  under  the  action 
of  cutting  with  the  threading  tool.  As  a  last  resort 
water  annealing  was  tried.  The  blanks  were  heated 
to  a  low  red  and  allowed  to  cool  until  they  reached  a 
point  where  fine  dry  sawdust  would  not  sparkle 
when  dropped  on  them,  and  then  plunged  in  warm 
soapy  water.  After  being  treated  in  this  manner 
there  was  no  tearing  of  the  stock  and  results  were 
perfectly  satisfactory.  The  writer  does  not  wish 
to  be  understood  as  advocating  this  method  of 
annealing.  On  the  contrary  he  discourages  its  use 
only  in  exceptional  cases,  but  there  are  cases  where,  if 
carefully  carried  on,  very  good  results  may  be  ob- 
tained. The  cooling,  however,  must  be  uniform 
and  this  is  difficult  to  accomplish  unless  extreme  care 
is  exercised  as  the  lighter  sections  and  edges  have  a 
tendency  to  cool  more  rapidly  than  the  balance  of 
the  piece. 

In  one  shop  where  it  is  practiced  on  rather  a  large 
scale  pieces  of  cast  iron  having  a  hole  somewhat 
larger  than  the  piece  to  be  annealed  drilled  in  from 


MISCELLANEOUS   WORK.  275 

one  end  one  inch  deeper  than  the  length  of  the  piece. 
These  are  heated  red  hot,  the  red-hot  piece  of  steel 
inserted  in  the  hole,  the  end  covered  and  the  whole 
allowed  to  cool  until  the  steel  is  to  the  desired 
temperature,  when  it  is  removed  from  the  case  and 
quenched  in  warm  oil. 

Examples  of  Hardening. — As  different  kinds  and 
forms  of  tools  require  different  treatment,  it  seems 
advisable  to  consider  them  separately  rather  than  to 
attempt  to  give  general  instructions.  The  one 
doing  the  hardening  should  consider  each  tool,  or 
each  batch  of  tools,  to  be  treated  as  a  problem,  the 
solution  of  which  depends  on  several  conditions, 
namely,  the  use  to  which  it  is  to  be  put;  the  steel 
from  which  it  is  made;  the  size  and  shape,  and  the 
treatment  the  steel  has  received  before  it  comes  to  the 
heat-treating  room  to  be  hardened,. 

Let  us  first  consider  a  piercing  punch  to  be  used 
in  connection  with  a  punch-press  die  as  shown  in 
Fig.  297.  In  order  to  determine  the  temperature  to 
which  it  should  be  heated,  a  knowledge  of  the  kind  of 
steel  used  is  necessary.  If  the  carbon  is  compara- 
tively low,  say  0.9  to  i  per  cent,  it  will  require  a 
higher  heat  than  if  made  from  steel  containing  1.25 
to  1.4  per  cent.  For  the  former,  a  temperature  of 
1450°  F.  will  be  required,  while  for  the  latter  only 
1425°  F.  should  be  given.  The  size  of  the  punch  is  a 
determining  factor  also,  as  one  \"  diameter  will  not 
require  as  high  a  heat  as  one  2"  diameter.  An  ab- 
solutely uniform  heat  is  essential.  Fig.  298  shows 
one  of  these  punches  that  was  not  uniformly  heated, 
and  when  hardened,  it  was  in  the  condition  shown. 


276  FORGE-PRACTICE. 

Some  of  these  punches  broke  in  the  bath  while  others 
broke  in  use,  all  showing  the  same  general  appearance. 
When  it  was  suggested  that  they  had  not  been  uni- 
formly heated,  the  claim  was  made  that  this  could 
not  be  so,  as  the  most  modern  appliances  were  used, 
a  certain  temperature  was  maintained  in  the  fur- 
nace, and  the  pieces  left  in  the  furnace  a  certain 


FIG.  297. 

length  of  time,  the  length  of  time  having  been 
determined  by  experiment. 

A  punch  from  the  same  lot  was  carefully  heated  in 
a  charcoal  fire  in  a  blacksmith's  forge  and  quenched 
in  the  same  bath  used  for  the  others,  and  did  not 
show  any  weakness  when  tested  or  when  put  to  use. 
Further  investigation  showed  that  the  pieces  had 
not  been  uniformly  heated.  As  a  result,  the  hard- 
ener was  given  orders  to  carefully  observe  the  heat 
given  each  piece  before  quenching. 

Cold  Chisels. — The  efficiency  of  a  cold  chisel  de- 
pends, in  a  large  measure,  on  the  treatment  it 


MISCELLANEOUS  WORK.  277 

receives  when  being  forged.  A  piece  of  steel  if  im- 
properly treated  in  the  process  of  forging  cannot  be 
hardened  and  tempered  so  it  will  do  the  amount  of 
work  it  should. 

As  a  rule,  a  chisel  to  be  used  for  ordinary  work  is 
made  from  steel  containing  0.9  to  i.i  per  cent  car- 
bon. For  many  small  chisels  to  be  used  for  such 
work  as  die  sinking,  when  light  cuts  are  to  be  taken, 
and  where  the  ability  to  hold  a  keen  edge  is  essential, 
steel  containing  a  higher  percentage  is  used.  The 
higher  the  carbon  content  the  greater  care  necessary 
when  forging. 

Small  chisels  should  never  be  quenched  in  an  ex- 
tremely cold  bath,  as  this  causes  brittleness,  and 
extreme  toughness  is  the  quality  needed.  For 
chisels  of  ordinary  size  (i")  a  bath  whose  tempera- 
ture is  about  70°  F.  gives  good  results.  As  70°  F.  is 
about  the  temperature  of  the  ordinary  room  there  is 
little  need  of  gauging  the  heat.  In  extremely  warm 
weather  it  may  be  necessary  to  add  cool  water  occa- 
sionally. Very  small  chisels  many  times  give  excel- 
lent results,  especially  if  the  carbon  content  of  the 
steel  is  high,  if  the  bath  is  slightly  warmer  than  that 
mentioned. 

The  chisel  should  be  uniformly  heated  to  the  da- 
sired  temperature  for  an  inch  or  more  above  the 
point  to  which  the  hardness  is  to  extend.  It  should 
be  worked  up  and  down  in  the  bath  to  prevent  a 
"water  line,"  and  around,  to  avoid  steam.  When 
it  is  properly  hardened,  remove  from  the  bath  and 
brighten  one  side  with  the  buff  stick  and  draw  the 
temper. 


278  FORGE-PRACTICE . 

Many  hardeners  draw  the  temper  of  medium  size 
and  large  chisels  by  means  of  the  heat  left  in  the  body 
of  the  steel  after  the  cutting  end  is  hardened,  help- 
ing this  out  when  necessary  by  holding  it  in  the 
flame  of  the  fire.  Others  contend  that  better  re- 
sults follow  when  the  piece  is  entirely  cooled  and 
then  reheated  for  drawing.  Either  practice  is  good 
if  carefully  carried  on.  As  the  cutting  end 
of  a  chisel  is  thinner  than  the  portion 
immediately  back  of  it,  extreme  care  must 
be  observed  when  heating  for  hardening 
or  an  uneven  heat  will  result,  and  a  break 
as  shown  in  Fig.  299  will  appear  when 
quenching,  or  when  the  tool  is  used. 

As  repeatedly  stated,  steel  shows  the 
effects  of  the  last  heat  it  receives,  and  as 
high  heats  perceptibly  weaken  it  extreme 
care  should  be  taken  when  hardening 
chisels.  Do  not  heat  any  hotter  than  is 
necessary  to  refine  the  steel.  Many  times 
cold  chisels  receive  less  attention  than 

\ /      tools  that  cost  more  in  making,  but  if  one 

FIG.  299.  will  consider  that  a  chisel  properly  forged, 
hardened  and  tempered  will  do  many  times 
more  work  in  a  day  than  one  improperly  treated,  it 
will  be  seen  that  the  same  care  should  be  exercised 
as  when  hardening  a  more  costly  tool. 

In  many  shops  an  account  is  kept  of  the  amount  of 
work  done  with  a  tool;  original  cost  and  upkeep 
placed  in  one  column  and  the  amount  of  work  ac- 
complished with  it,  in  the  other  column,  thus  making 
it  possible  to  find  the  tool  cost  per  piece  of  work. 


MISCELLANEOUS   WORK.  279 

This  practice  in  the  case  of  a  cold  chisel  may  not  be 
feasible,  but  the  same  care  should  be  exercised  in  its 
treatment  as  would  be  in  the  case  of  a  costly  die  or 
milling  machine  cutter  with  which  an  account  was 
kept. 

Tempering. — Any  tool  hardened  at  the  proper 
temperature  will  stand  up  in  use  with  less  ''drawing 
back"  than  if  given  more  heat.  It  is  necessary  at 
times  to  draw  the  temper  of  a  chisel  much  more  than 
it  should  be  to  give  it  the  necessary  toughness,  be- 
cause it  was  overheated  in  hardening.  If  the  tool 
is  heated  150°  above  the  refining  heat,  it  will  be 
necessary  to  draw  the  temper  considerably  more 
than  it  should  be,  thus  we  get  extreme  brittleness 
from  the  overheating,  and  softness  from  the  tem- 
pering. 

It  is  not  possible  to  give  the  exact  temperature  to 
which  a  chisel  should  be  drawn,  as  the  use  to  which 
it  is  to  be  put  must  in  a  great  measure  determine  this. 
Small  chisels  used  in  die  sinking  and  similar  work 
are  many  times  drawn  to  a  full  straw  color  (460°  F.), 
while  those  used  for  rough,  heavy  work  are  drawn  to  a 
purple.  The  writer's  experience  has  convinced  him 
that  for  ordinary  work,  chisels  of  the  average  size 
give  good  results  if  drawn  to  a  very  deep  brown  with 
the  red  and  purple  spots  just  showing,  then  check  in 
warm  oil.  Many  hardeners  check  a  chisel,  after 
drawing,  in  cold  water,  which  tends  to  set  up  a  cer- 
tain amount  of  brittleness  that  is  not  apparent  if  oil 
is  used. 

Punch-press  Dies. — There  are  many  kinds  and  pat- 
terns of  dies  used  in  punch-press  work.  We  will 


280  FORGE-PRACTICE. 

consider  first  a  few  patterns  of  blanking  dies.  Prob- 
ably no  one  class  of  tools  gives  the  hardener  in  a  job 
shop  more  concern  than  blanking  dies.  If  the  size 
and  design  are, such  that  hardening  is  a  simple  task, 
the  work  is  done  in  the  shop  where  it  is  made ;  on  the 
other  hand,  if  the  die  is  liable  to  go  to  pieces  as  a 
result  of  heat  treatment,  it  is  sent  to  a  place  where  a 
specialty  is  made  of  such  work.  There  are  many 
things  to  consider  when  hardening  a  die.  First,  the 
steel  from  which  it  is  made;  second,  the  treatment  it 
has  received  in  forging  or  annealing;  third,  the 
treatment  it  has  received  by  the  die  maker,  and 
fourth,  the  use  to  which  it  is  to  be  put. 

Of  course  it  is  necessary  that  the  hardener  know 
whether  the  steel  is  low  or  high  carbon,  or  some  alloy 
steel  (as  oil  hardening  steel)  that  requires  special 
treatment.  The  treatment  it  may  have  received  in 
forging,  annealing  or  by  the  die  maker  is  difficult  to 
find  out  and  many  times  has  to  be  ignored.  If  the 
die  is  to  be  used  in  punching  hard  or  heavy  stock,  it 
may  require  different  temper  drawing  than  if  it  is 
to  work  on  soft  or  thin  material. 

If  we  are  uncertain  as  to  the  forging  or  annealing 
it  is  a  good  plan  to  heat  the  die  to  a  red,  slightly 
above  the  hardening  heat,  remove  it  from  the  fire 
and  allow  it  to  cool.  This  is  done  to  remove  any 
strains.  It  may  then  be  reheated  to  the  desired 
temperature  and  immersed  in  the  bath.  When 
placing  in  the  bath  grasp  it  by  means  of  tongs  in 
such  a  manner  as  not  to  cover  any  essential  part,  and 
lower  it  endwise  as  shown  in  Fig.  300,  swinging  it  back 
and  forth  so  as  to  force  the  liquid  through  the  open- 


MISCELLANEOUS   WORK. 


28l 


ings.  A  still  bath  of  brine  of  generous  proportions 
works  nicely.  While  a  bath  of  the  description  shown 
in  Fig.  301  with  a  jet  coming  in  from  the  side  is  often 
used  for  this  purpose,  better  results  follow  the  use  of 
a  still  bath,  as  uneven  cooling  may  result  in  warping 
the  die. 


FIG.  300. 

When  the  die  has  cooled  to  the  temperature  of  the 
bath,  remove  and  hold  over  a  fire  and  heat  until 
moisture  applied  with  the  finger  will  steam  from  the 
heat  in  the  steel.  When  doing  this,  turn  the  die 
repeatedly  so  that  it  will  absorb  the  heat  uniformly, 
which  is  done  to  remove  hardening  strains.  The 


282 


FORGE-PRACTICE. 


surface  may  now  be  brightened  and  the  temper 
drawn. 

Dies  to  be  used  in  blanking  pieces  from  soft  steel 
may  be  drawn  to  a  full  straw  color. 

In  Fig.  302  is  shown  a  die  made  from  thin  stock. 

;  As  this  is  used  in  punching  cold  rolled  strip  stock 

of  0.80  per  cent  carbon  it  is  necessary  to  use  extreme 

care  in  heating  and  quenching.     The  cut  shows  the 


FIG.  301. 

die  with  the  stripper  attached.  This  is  removed 
when  the  die  is  hardened.  The  screw  holes  should  be 
filled  with  fire  clay  dough  as  it  is  not  necessary  to 
harden  the  walls  of  these,  and  the  danger  of  cracking 
is  reduced  by  so  doing.  As  stated  this  die  is  made 
from  thin  stock  (f  "),  as  a  result  the  top  and  bottom 
must  be  uniformly  cooled  or  the  die  will  spring. 
A  bath  made  by  dissolving  10  tablespoonfuls  of  salt 
to  a  gallon  of  water  is  used.  The  bath  is  kept  as 
nearly  as  possible  at  a  temperature  of  80°  F.  The 


MISCELLANEOUS   WORK. 


283 


die  is  immersed  endwise  and  worked  back  and  forth 
to  force  the  liquid  through  the  opening  and  to  cool 
both  flat  surfaces  as  uniformly  as  possible.  The 
temper  is  drawn  by  heating  in  oil  to  450°  F. 

Fig.  303  represents  a  die  that  requires  extreme  care, 
and  the  display  of  considerable  ingenuity  in  hard- 
ening as  the  thin  partition  between  the  openings 


Stripper 


Die 


Stripper 


,Die 


FIG.  302. 

c  c  is  liable  to  break  away  from  the  body  of  the  die  on 
account  of  its  hardening  so  much  more  rapidly  than 
the  heavier  portions,  and  as  the  heavier  portions 
would  continue  to  contract  after'  the  partition  was 
hard  and  unyielding.  To  overcome  this  tendency 
the  walls  of  the  partition  should  be  covered  with  oil 
by  means  of  a  small  brush  just  before  immersing  the 
die  in  the  bath,  thus  retarding  the  hardening  and 
consequent  contraction  at  this  point.  The  stripper 
plate  screw  holes  and  stop-pin  hole  should  be  plugged 


284 


FORGE-PRACTICE. 


with  fire  clay  dough  before  the  die  is  placed  in  the 
fire. 

Hardening  Redrawing  Dies. — Redrawing  dies  and 
other  articles  that  must  have  an  extremely  hard  sur- 
face on  the  walls  of  the  hole,  and  where  a  soft  exterior 
is  desirable  may  be  satisfactorily  hardened  by  heating 
to  the  proper  temperature,  then  enclosing  in  the  fix- 
ture shown  in  Fig.  304  and  allowing  a  stream  of  water 


00 


FIG.  303. 

to  run  through  the  hole  as  shown.  Do  not  allow  the 
lower  end  of  the  fixture  to  enter  any  body  of  water  as 
this  would  retard  the  flow  of  the  stream  through 
the  hole,  steam  would  form  and  poor  results  would 
follow. 

Dies  and  other  pieces  having  holes  which  go  only 
part  through  them,  whose  walls  must  be  hardened 
cannot  be  treated  in  a  satisfactory  manner  unless 
some  means  is  provided  for  forcing  the  liquid  to  the 
bottom  of  the  holes.  This  is  best  accomplished  by 


MISCELLANEOUS   WORK. 


running  a  pipe  nearly  to  the  bottom  of  the  hole  as 
shown  in  Fig.  305  where  one  piece  of  pipe  is  fitted 
over  another  thus  enabling  one  to  use  the  device 
where  holes  of  varying  depths  are  encountered.  In 
hardening  pieces  of  this  kind  steam  is  the  principal 
obstacle  to  be  overcome,  the  water  going  down  into 
the  hole  forces  the  steam  out,  and  at  the  same  time 


FIG.  304. 


FIG.  305. 


acts  on  the  walls  of  the  hole.  When  heating  such 
pieces  it  is  advisable  to  fill  the  hole  with  a  mixture  of 
4  parts  powdered  charred  leather  and  i  part  table 
salt  before  placing  in  the  furnace  to  prevent  oxida- 
tion of  the  surfaces  and  render  them  perfectly  clean 
and  ready  for  the  action  of  the  liquid. 

In  cases  of  the  kind  under  consideration  care  should 
be  exercised  that  the  liquid  does  not  enter  the  hole 


286 


FORGE-PRACTICE. 


under  too  great  pressure.  The  pressure  should  be 
just  enough  to  insure  the  removal  of  steam  and  to 
carry  the  water  out  before  it  heats  to  any  extent. 

A  die  with  a  hole  having  two  or  more  sizes  as 
shown  in  Fig.  306  presents  a  problem  that  causes 
considerable  perplexity  at  times.  Unless  the  piece  is 
heated  in  a  manner  that  excludes  all  air  from  it,  scale 
is  apt  to  form,  and  while  this  scale  might  crack  away 
and  pass  off  with  the  liquid  used  in  quenching  if 

the  hole  was  of  one  size, 
the  scale  in  the  corners 
formed  by  the  change  of 
size  is  not  so  easily  gotten 
rid  of  and  unless  some 
method  is  devised  for  "strik- 
ing" it,  good  results  can- 
not be  obtained.  One 
method  is  to  harden  with  a 
stream  of  brine,  but  many 

times,  especially  in  the  case  of  high  carbon  steel, 
brine  may  be  considered  too  harsh.  Another  method 
is  to  run  brine  through  the  hole  for  a  few  seconds 
and  then  to  immediately  change  to  water  as  shown 
in  Fig.  307.  A  method  practiced  with  good  results 
in  one  plant  is  to  sprinkle  a  very  small  amount  of 
powdered  cyanide  of  potassium  into  the  hole  just 
before  removing  the  die  from  the  fire,  then  quench  as 
shown  in  Fig.  304. 

Where  the  condition  of  the  hole  under  considera- 
tion exists  care  should  be  used  in  determining  the 
velocity  with  which  the  liquid  is  projected  into  the 
hole.  The  size  of  the  stream  and  the  velocity  should 


FIG.  306. 


MISCELLANEOUS   WORK. 


287 


be  graduated  so  that  the  water  will  not  bound  back 
and  retard  the  water  going  into  the  hole  or  satis- 
factory results  will  not  follow.  In  fact,  the  pre- 
caution just  mentioned  should  be  observed  when 
quenching  any  die  where  the  walls  of  the  hole  are  the 
part  desired  hard. 


FIG.  307. 

Burnishing  Dies. — Fig.  308  shows  a  die  used  in  bur- 
nishing the  edges  of  a  blank  that  had  been  pre- 
viously punched  from  sheet  steel.  Burnishing  is 
resorted  to  where  edges  must  be  highly  finished,  and 
of  accurate  diameters,  and  also  furnishes  a  means 
of  doing  the  work  at  a  greatly  reduced  price  as  com- 
pared with  polishing.  As  the  walls  of  the  hole  taper, 
being  smaller  at  the  bottom,  an  immense  strain  tend- 
ing to  burst  the  die  is  given  it.  As  a  consequence 
the  heat  treatment  must  be  such  as  to  insure  the 


288 


FORGE-PRACTICE. 


greatest  possible  strength.  Forcing  a  blank  through 
a  hole  smaller  than  its  own  diameter  also  sets  up  a 
tendency  to  maximum  wear  of  the  walls  of  the  hole 
necessitating  an  extremely  hard  surface.  Dies  of 
this  class  must  have  the  surface  of  the  holes  highly 
polished  in  order  to  effectually  burnish  the  work. 
When  the  hole  is  machined  somewhat  smaller  than 
finish  size,  and  is  ground  and  lapped  after  hardening 
no  particular  attention  need  be  given  to  retaining 


FIG.  308. 

the  finish  of  the  hole,  but  where  the  working  finish 
is  given  before  hardening  extreme  care  must  be  exer- 
cised to  prevent  even  the  slightest  degree  of  oxida- 
tion. 

Summing  up  the  conditions  just  mentioned  we 
finfl  that  the  die  must  be  hardened  so  as  to  produce 
the  maximum  of  hardness  and  strength  with  free- 
dom from  oxidation.  Work  of  this  kind  should 
always  be  enclosed  in  a  box  surrounded  with  a  pack- 
ing material  composed  of  equal  parts  of  charred 


MISCELLANEOUS   WORK. 


289 


leather  and  charcoal.  Before  placing  in  the  box  the 
walls  of  the  hole  should  be  coated  with  file  maker's 
paste,  which  is  made  of  charred  leather,  flour  and 
salt,  the  exact  proportions  of  which  are  given  else- 
where. The  die  should  be  heated  to  a  uniform  red 
and  hardened  by  running  a  stream  of  water  through 
the  hole.  The  die  should  be  placed  in  a  cage  as 


•fV 


Cover 


"-1 


Cage 


IsiiiSiiiiisi 

FIG.  309. 

shown  in  Fig.  309  after  taking  from  the  box  and 
before  quenching.  As  the  walls  of  the  hole  and  a 
small  portion  of  the  top  are  the  only  parts  hardened, 
any  alteration  in  the  size  of  the  hole  is  not  probable. 
The  outer  portions  not  being  hardened  are  extremely 
tough  and  will  resist  the  tendency  to  burst  from  the 
strains  incident  to  forcing  the  pieces  through.  The 
paste  is  an  added  precaution  against  oxidation  and 
protects  the  surfaces  until  the  die  is  acted  on  by  the 


2QO  FORGE-PRACTICE. 

water.  In  one  shop  that  has  come  to  the  writer's 
notice  the  die  is  rem  :>ved  from  the  cage  after  the 
surface  walls  are  thought  to  have  been  sufficiently 
hardened  and  immediately  plunged  in  light  oil. 
In  this  way  the  outer  portion  is  somewhat  stiffened. 
I  am  inclined  to  the  opinion  that  this  is  not  a  safe 
practice  especially  if  the  pieces  to  be  burnished  are 
heavy,  as  heavy  or  hard  stock  would  require  a  deeper 
penetration  of  hardness  than  light  or  soft  stock. 
Then  again  a  great  deal  must  be  left  to  the  judg- 
ment of  the  operator  as  to  the  exact  time  the  piece 
should  be  plunged  in  the  oil. 

The  object  of  using  the  packing  material  when  the 
die  is  heated  is  to  protect  it  from  the  action  of  the 
air,  to  secure  uniform  heating  and  to  prevent  decar- 
bonizing in  any  way.  It  is  removed  from  the  box 
as  soon  as  it  is  uniformly  heated  to  the  proper  tem- 
perature and  quenched. 

Forming  and  Bending  Dies. — For  dies  used  in  form- 
ing and  bending  sheet  metal  a  somewhat  higher  tem- 
perature must  be  employed  than  when  hardening 
tools  used  in  cutting,  as  the  particular  condition  to 
be  overcome  is  a  tendency  to  sink  or  cave  in,  and  not 
only  is  a  deeper  penetration  necessary  than  is  the 
case  with  cutting  tools,  but  the  interior  structure 
must  be  stiff er  to  withstand  the  tendency  to  sink. 
This  condition  can  only  be  brought  about  by  a 
higher  temperature  which  causes  the  necessary 
changes  in  the  steel. 

Cutting  or  Dinking  Dies. — Dies  used  for  cutting 
leather,  cloth,  paper,  etc.,  are  called  cutting,  or  dink- 
ing  dies.  They  are  many  times  made  from  ' '  backed ' ' 


MISCELLANEOUS  WORK.  59 1 

steel,  that  is,  the  portion  that  bears  the  cutting  edge 
is  of  hardening  steel  while  the  balance  is  of  wrought 
iron.  The  two  are  welded  together  in  the  steel  mill. 
When  heating  for  hardening  special  furnaces,  so 
designed  that  the  cutting  edge  to  the  welded  line  is 
uniformly  heated  to  the  desired  temperature  are 
used  in  some  shops.  Many  times  a  hard  coal  fire 
of  fine  coal  is  used  in  heating  as  the  fire  can  be  run 
so  that  a  uniformly  low  temperature  can  be  obtained. 
The  cutting  edge  can  be  bedded  down  into  the  coals 
with  no  danger  of  overheating.  When  dipping,  a 
bath  of  light  oil  or  warm  water  is  used.  If  cotton- 
seed oil  is  found  to  be  too  heavy  a  small  amount  of 
light  mineral  oil  may  be  added  to  obtain  the  right 
consistency.  In  drawing  the  temper  of  cutting  dies 
the  material  to  be  cut  must  determine  the  amount  of 
drawing.  The  range,  however,  is  generally  from  a 
brown  to  a  dark  blue  (500°  to  570°  F.). 

Curling  Dies. — Curling  and  wiring  dies  and  punches 
as  shown  in  Fig.  310  should  be  quenched  with  their 
working  faces. uppermost,  and  by  having  a  stream 
of  water  running  down  onto  them.  As  such  dies 
and  punches  are  not,  as  a  rule,  made  from  steel  con- 
taining a  very  high  percentage  of  carbon  they 
require  a  somewhat  higher  temperature  than  tools 
made  from  high  carbon  steel.  As  repeatedly  stated 
the  steel  should  not  be  overheated  but  simply  given 
the  proper  temperature  for  desired  results. 

Taps. — As  this  class  of  tool  has  its  cutting  portions 
in  the  form  of  slender  projections  extreme  care  should 
be  exercised  when  heating  for  hardening  or  the 
teeth  will  become  overheated  before  the  body  of  the 


2Q2  FORGE-PRACTICE. 

tool  reaches  the  desired  temperature.  A  very  good 
practice  is  to  have  a  number  of  pieces  of  gas  pipe 
somewhat  larger  and  longer  than  the  taps.  Each 
tap  may  be  placed  in  a  pipe  before  it  goes  into  the 
furnace.  When  heating  as  described  there  is  less 
danger  of  overheating  the  teeth.  A  practice  fol- 
lowed in  some  shops  where  screw  die  hobs  are  hard- 


FIG.  310. 

ened  in  quantities  is  to  fill  the  teeth  with  the  "  file- 
maker's  paste"  described  elsewhere.  When  the 
paste  dries  the  hobs  are  placed  in  pipes  and  heated. 
While  taps  can  be  hardened  in  a  still  bath  of  brine, 
or  water,  better  results  follow  the  use  of  one  of  the 
type  shown  in  Fig.  278  as  the  liquid  is  forced  between 
the  threads,  thus  insuring  uniform  cooling.  Taps 
should  not  be  quenched  in  very  cold  baths  as  a  tern- 


MISCELLANEOUS  WORK.  293 

perature  of  70°  to  80°  F.  gives  better  results.  Taps 
larger  than  i"  diameter  should  be  taken  from  the 
bath  shortly  after  "singing"  ceases  arid  cooled  in  oil. 
While  the  temper  of  taps  may  be  drawn  to  color 
more  uniform  results  follow  if  an  oil  drawing  furnace 
is  used.  If  the  temper  is  to  be  drawn  to  color  the 
surface  of  the  flutes  may  be  brightened  by  grinding 
with  some  form  of  abrasive  wheel  making  sure  that 
a  small  amount  is  ground  off  the  face  of  the  cutting 
teeth.  This  is  necessary  as  this  surface  is  liable  to 
contract  in  hardening  more  than  that  immediately 
back  of  it  where  there  is  sufficient  stock  to  prevent 
contraction ;  as  a  result  the  cutting  edge  of  the  tooth 
is  slightly  lower,  and  while  this  amount  is  very  small 
it  is  sufficient  to  cause  the  tap  to  bind  when  cutting, 
especially  if  it  is  used  on  metals  where  it  cuts  very 
close  to  its  own  size. 

The  temper  to  which  taps  should  be  drawn  varies 
with  the  size  and  the  use  to  which  they  are  to  be  put. 
Those  used  for  sizing,  and  which  remove  but  a  very 
little  stock  are  sometimes  left  as  they  come  from  the 
hardening  bath,  more  often  though  they  are  drawn 
to  a  pale  yellow  (430°  F.).  For  ordinary  use  they 
are  drawn  to  450°  to  460°  F.  Small  taps  used  in 
screw  machines  are  many  times  drawn  to  a  brown 
yellow  (500°  F.),  or  to  a  light  purple  (530°  F.),  de- 
pending on  the  strains  they  are  to  receive.  If  quench- 
ing is  necessary  to  keep  the  temper  from  running 
too  much,  warm  oil  should  be  used. 

Steel  for  Taps. — In  most  small  shops  and  also  in 
some  of  considerable  size  a  certain  "temper"  of 
crucible  tool  steel  is  used  for  most  cutting  tools. 


2Q4  FORGE-PRACTICE. 

While  this  practice  does  away  with  the  mixing  of 
various  grades  and  the  annoyance  caused  thereby, 
mixing  is  not  necessary  and  seldom  happens  where 
a  system  of  marking  and  keeping  in  separate  racks  is 
employed. 

Maximum  results  follow  the  use  of  steels  suited  for 
the  individual  tool,  or  for  tools  to  be  used  for  a  cer- 
tain class  of  work.  While  "straight"  carbon  steels 
containing  the  proper  percentage  of  carbon  give  good 
results  on  some  classes  of  work,  certain  of  the  alloy 
steels  give  very  much  better  results  on  other  classes. 
For  instance,  i.i  to  1.25  per  cent  carbon  gives  fair 
results  when  used  for  taps  to  work  on  brass  and  cast 
iron,  yet  a  steel  of  this  same  carbon  content  with  an 
addition  of  2.0  per  cent  tungsten  will  under  the  same 
conditions  do  many  times  the  amount  of  work. 
This  addition  of  tungsten,  however,  calls  for  a  higher 
hardening  heat ;  the  makers  recommending  1 5  2  5  °  F. 

Vanadium  steel  made  especially  for  taps,  etc., 
gives  excellent  results  so  far  as  strength  is  concerned 
and  is  to  be  recommended  where  a  slight  change  in 
pitch  is  not  a  serious  matter.  Straight  carbon  and 
tungsten  steels  when  properly  treated  generally 
contract  in  length,  but  this  contraction  can  be  antici- 
pated when  the  tool  is  threaded,  but  vanadium  steels 
may  either  contract  or  expand  and  for  this  reason 
cannot  be  used  where  accuracy  of  pitch  is  essential. 

Taps  that  are  pack  hardened  do  not,  as  a  rule, 
change  in  pitch  if  the  blanks  are  properly  annealed 
and  low  heats  are  obtained  when  hardening. 

High  speed  steel  is  especially  suited  to  tap  making, 
especially  for  those  used  on  screw  machines.  It 


MISCELLANEOUS  WORK. 


295 


should  be  heated  to  about  2150°  F.  for  hardening. 
In  tempering  they  should  be  drawn  to  form  500°  to 
950°  F.  according  to  size  and  the  shock  they  are  to 
receive  when  in  use. 

Threading  Dies. — Threading  dies  are  made  from  a 
variety  of  steels.  This  is  necessary  on  account  of 
different  demands  on  the  tool  resulting  from  the 
variety  of  metals  to  be  threaded,  and  the  opinions 
of  men  in  charge  of  work.  When  the  metal  to  be 
threaded  is  easily  machined  and  free  from  grit, 
almost  any  good  tool 
steel  01  the  proper  carbon 
content  gives  good  re- 
sults if  properly  treated. 
In  shops  where  the  screws 
are  made  from  iron  wire, 
or  from  stock  that,  on 
account  of  its  composi- 
tion, 01  from  other 
causes,  subjects  the  die 
to  abrasive  action,  it 
is  many  times  advisable  to  use  a  suitable  alloy 
steel  that  will  resist  the  tendency  to  wear  from  the 
causes  mentioned.  If  alloy  steels  are  used  the 
treatment  must  correspond  to  the  requirements  of 
the  metal ;  however,  instructions  usually  accompany 
steels  that  require  special  treatment. 

Threading  dies  are  made  in  a  variety  of  forms. 
The  ordinary  round,  or  button  die  shown  in  Fig.  311 
is  made  either  solid  or  adjustable.  If  a  solid  die  is 
to  be  hardened  the  chief  requirement  is  suitably 
hardened  threads,  this  hardness  extending  out  into 


FIG.  311. 


296  FORGE-PRACTICE. 

the  body  of  the  tool  for  a  distance  that  insures  good 
results.  In  some  shops  it  is  customary  to  harden 
the  whole  die  to  as  uniform  a  degree  as  possible  and 
then  draw  back  the  portions  that  should  not  be  as 
hard  as  the  cutting  portions.  In  other  shops  it  is 
considered  best  practice  to  harden  the  threaded 
portions  and  for  a  distance  out  into  the  die  leaving 
the  balance  soft,  while  the  requirements  in  other 
places  make  it  necessary  to  harden  the  portion  just 
mentioned  and  stiffen  the  balance  of  the  die  in  oil. 

As  the  threaded  portion  is  the  essential  part  of 
the  die,  and  as  most  " button"  dies  are  so  made  that 
either  end  may  be  used  in  cutting,  it  is  apparent  that 
an  equality  of  hardness  throughout  the  threaded 
hole  is  necessary.  This  result  can  be  accomplished 
by  immersing  the  die  edgewise  in  a  still  bath  of  brine 
working  back  and  forth  to  force  the  liquid  through 
the  hole.  If  the  outer  portion  is  desired  soft  the 
die  may  be  held  in  a  fixture  so  constructed  that  the 
portion  desired  soft  is  covered. 

Milling  Machine  Cutters. — Probably  no  one  class  of 
tool  is  a  source  of  greater  anonyance  to  the  hardener 
than  the  cutters  used  on  milling  machines  and  gen- 
erally known  as  " mills."  The  troubles  experienced 
should  not,  in  all  cases,  be  attributed  to  the  hard- 
ener. This  form  of  tool  is  costly  to  produce  and  in 
many  factories  is  used  in  large  quantities.  Effi- 
ciency is  many  times  based  on  the  length  of  life  of  the 
tool  regardless  of  the  quantity  of  work  produced, 
and  this  has  led  to  the  use  of  slow  speeds  and  fine 
feeds,  where,  under  different  conditions,  namely, 
maximum  speeds  and  feeds  for  properly  designed 


MISCELLANEOUS  WORK.  297 

tools,  those  considered  would  have  been  found  sadly 
wanting  and  the  hardener  blamed  because  they 
would  not  do  the  things  easily  accomplished  by 
properly  designed  tools  hardened,  and  tempered 
exactly  as  these  were.  A  mill  with  a  great  number  of 
fine  teeth  where  but  few  are  required  collects  chips 
between  its  teeth  and  if  coarse  feeds  are  resorted  to 
the  teeth  will  break.  As  the  cooling  liquid  cannot 
have  free  access  to  the  teeth  slow  speeds  must  be 
resorted  to  or  heating  will  result.  If  the  mill  is  run 
at  a  high  speed,  which,  under  right  conditions,  would 
be  easily  possible  it  will  heat  and  the  temper  will  be 
drawn  to  a  point  that  causes  rapid  dulling  of  the 
teeth,  consequently,  as  the  tool  is  too  soft,  and  the 
teeth  are  too  weak  to  stand  up,  the  fault  is  usually 
put  up  to  the  hardener,  and  he,  poor  fellow,  knowing 
nothing  about  tool  design,  does  not  know  what  to  do 
to  bring  about  correct  results.  The  writer  has  seen 
mills  having  forty  cutting  teeth,  which  were  being 
used  in  milling  a  semi-circular  groove  through  a  piece 
of  work,  that  had  to  be  run  at  a  speed  and  feed  that 
made  it  impossible  to  produce  more  than  30  pieces 
in  ten  hours.  These  were  replaced  by  others  made 
from  steel  of  the  same  make  and  "temper,"  which 
contained  7  teeth  and  produced  125  pieces  in  the 
same  time.  Both  were  hardened  and  tempered  by 
the  same  man  and  as  nearly  as  possible  in  the  same 
manner. 

Slender  teeth  are  conducive  to  weakness.  Cutter 
teeth  should  always  be  made  of  a  shape  that  insures 
maximum  strength  because  if  a  tooth  springs  it 
cuts  deeper  into  the  work  than  it  should,  thus  put- 


298  FORGE-PRACTICE. 

ting  a  breaking  strain  on  the  tooth.  If  the  angle 
at  which  the  tooth  is  backed  off  in  grinding  is  not 
exact,  trouble  will  follow.  If  it  is  backed  off  too 
much,  the  fine  cutting  edge  does  not  receive  the 
support  it  should  and  as  a  result  flaxes  off,  or,  on  the 
other  hand  if  it  is  not  given  sufficient  angle  the  heel 
will  rub,  thus  causing  the  tool  to  heat  and  dull 
quickly.  These  are  conditions  that  the  hardener  is 
in  no  way  responsible  for,  yet,  unfortunately,  he  is 
many  times  scored  for  these  and  similar  troubles, 
the  cause  of  which  he  is  entirely  ignorant. 

The  writer's  attention  was  called,  a  short  time  ago, 
to  a  batch  of  slotting  mills  made  from  a  well-known 
brand  of  tool  steel.  These  mills  were  to  be  used  in 
cutting  slots  \"  deep  in  0.30  per  cent  open  hearth 
steel  forgings  that  were  well  annealed.  Several  of 
the  mills  were  tried,  but  could  not  be  made  to  work 
as  they  would  dull  quickly  and  could  not  be  forced 
into  the  stock.  Examination  showed  that  they  were 
not  given  sufficient  angle  in  backing  off  the  cutting 
edges.  After  being  reground  to  the  proper  angle 
they  were  pronounced  highly  efficient.  In  this  case 
the  opinion  of  those  in  authority  had  been  divided, 
by  some  the  hardener  was  considered  at  fault,  while 
others  claimed  the  steel  was  unfit  for  the  purpose. 
The  incidents  mentioned  in  connection  with  milling 
cutters  are  characteristic  of  troubles  that  are  met 
with  frequently  in  many  shops.  If  the  cause  of 
the  trouble  is  not  discovered  what  is  more  natural 
than  to  lay  it  to  the  steel,  or  the  hardener. 

If  the  hardener  is  blamed  for  troubles  that  orig- 
inate outside  of  his  department,  and  he  hasn't  suf- 


MISCELLANEOUS  WORK.  299 

ficient  knowledge  of  tool  design  to  enable  him  to 
locate  the  trouble,  he  naturally  changes  his  method  of 
treatment  of  that  class  of  tool  with  results  that  are 
not  to  his  credit.  Troubles  of  the  character  just 
mentioned  are  not  peculiar  to  milling  cutters,  but 
undoubtedly  are  of  more  frequent  occurrence  with 
this  class  of  tool  than  any  other. 

Steel  for  Milling  Cutters. — Milling  cutters  are  made 
from  steel  containing  all  the  way  from  i.oo  to  1.60 
per  cent  carbon.  It  may  also  contain  varying  pro- 
portions of  tungsten  and  other  elements.  The  vary- 
ing proportions  of  these  elements  necessitates  a  vari- 
ation of  temperatures  when  heating  for  hardening  in 
order  to  secure  the  best  possible  results. 

Hardening. — The  size  and  design  of  the  tool  also  has 
a  bearing  on  the  hardening  temperature.  Extreme 
care  should  be  exercised,  when  heating,  that  the  teeth 
do  not  become  overheated  before  the  body  of  the  tool 
has  reached  the  desired  temperature,  which  must  be 
uniform  throughout  the  piece.  Should  any  portion  of 
any  piece  being  heated  for  hardening  become  overheated 
the  piece  should  be  removed  from  the  fire  and  allowed  to 
cool,  after  which  it  may  be  reheated  and  hardened. 
Although  muffle  furnaces  are  not  generally  used  at 
the  present  time,  on  account  of  the  comparatively 
high  cost  for  fuel  and  maintenance,  they  afford  an 
ideal  method  of  heating  tools  of  the  character  under 
consideration.  In  the  absence  of  a  muffle  furnace 
the  mill  may  be  heated  satisfactorily  in  an  ordinary 
oven  furnace  by  placing  over  it  a  piece  of  sheet  iron 
bent  so  as  to  prevent  the  direct  action  of  the  heat. 
This  protecting  piece  should  not  lie  directly  on  the 


300  FORGE-PRACTICE. 

work,  but  should  be  far  enough  from  it  so  that  the 
heating  will  be  from  radiation.  It  is  a  good  plan  to 
surround  the  teeth  with  dry  fire  clay  or  some  refractory 
material  during  the  first  stages  of  the  heating  to 
retard  the  action  of  the  heat  at  these  portions  until 
the  body  of  the  tool  has  reached  a  low  red  when  it 
may  be  raised  and  the  material  spread  over  the  floor 
of  the  chamber  and  the  mill  allowed  to  rest  on  it. 
The  mill  should  be  turned  over  and  around  occa- 
sionally as  it  commences  to  get  red  to 
insure  uniform  heating.  Toward  the 
latter  part  of  the  heating  operation 
it  is  well  to  raise  the  tool  from  the 
floor  of  the  chamber  by  means  of 
several  small  pieces  of  fire  brick,  that 
have  been  heated  in  the  chamber 
thus  allowing  the  heat  to  circulate 
around  all  parts  of  it.  Tongs  should 
seldom  or  never  be  used  when  quench- 
ing a  mill  as  they  prevent  the  water 
3:  having  free  access  to  every  part.  A 
FIG.  312.  hook  of  the  design  shown  in  Fig.  312 
answers  the  purpose  very  well.  If  a 
still  bath  is  used  long  cutters  should  be  immersed 
lengthwise  and  worked  up  and  down  and  around  in 
the  bath,  first  in  one  direction  then  in  another,  alter- 
nating the  movement  frequently.  If  a  bath  of  the 
design  shown  in  Fig.  278  is  used,  where  the  liquid  is 
projected  uniformly  against  the  teeth  it  is  only  nec- 
essary to  work  them  up  and  down  slowly  to  cause 
the  liquid  to  pass  through  the  hole.  Thin  mills 
should  be  dipped  vertically  to  prevent  springing, 


MISCELLANEOUS   WORK.  30! 

as  shown  in  Fig.  313.  A  method  employed  by  one 
very  successful  hardener  when  dipping  thin  mills 
consists  in  dipping  vertically  then  rotating  the  mill 
slowly  by  means  of  a  piece  of  wire  thus  bringing  it 
constantly  in  touch  with  agitated  water.  Another 
method  employed  in  a  shop  where  many  slotting 


FIG.  313.  FIG.  314. 

cutters,  of  from  J"  to  \"  thicknesses  are  made,  con- 
sists of  immersing  in  a  bath  of  water  having  a  supply 
pipe  bent  in  the  form  of  a  circle  as  shown  in  Fig.  314. 
Numerous  small  holes  are  drilled  on  the  inner  por- 
tion of  the  circular  pipe  to  project  small  streams 
toward  a  common  center.  The  mill  is  held  so  that 
these  streams  will  impinge  against  the  teeth. 


302  FORGE-PRACTICE. 

Mills  that  are  \"  or  more  in  length  should  be  kept 
in  the  bath  until  the  "singing"  incident  to  the  im- 
mersion of  red-hot  steel  in  water  ceases  and  then  be 
plunged  into  oil  and  left  until  cold.  While  some 
hardeners  gauge  the  time  of  singing  by  the  ear,  it  is 
better  practice  to  gauge  it  by  the  vibration  trans- 
mitted through  the  hook  used  in  holding  the  piece, 
to  the  hand.  A  few  seconds  after  this  ceases  the 
mill  should  be  transferred  to  the  oil.  The  oil  bath 
should  be  conveniently  near  the  first  quenching  bath 
so  that  there  will  be  very  little  time  lost  in  transferring 
from  one  to  the  other  as  it  is  never  safe  when  quench- 
ing to  allow  the  contraction  of  the  metal  to  stop  and 
expansion  to  set  in.  The  process  of  contraction 
should  be  constant  from  the  time  the  steel  is  im- 
mersed until  it  is  cold. 

Mills  that  are  \"  or  more  in  length  should  be 
heated  to  relieve  the  hardening  strains  as  soon  as 
taken  from  the  oil.  This  may  be  done  by  holding 
over  a  blaze;  keeping  the  mill  revolving  all  the 
time  and  thus  uniformly  heating  until  a  particle  of 
moisture  placed  on  the  piece  steams.  If  the  temper 
is  to  be  drawn  by  color,  time  can  be  saved  by  bright- 
ening the  backs  of  several  of  the  teeth  and  finishing 
the  tempering  operation  at  this  time.  Mills  made 
from  ordinary  carbon  steels  and  used  for  ordinary 
lines  of  work  are  tempered  to  a  light  straw  color 

(430°  P.). 

If  a, quantity  of  mills  are  to  be  tempered,  time  will 
be  saved  and  more  uniform  results  obtained  if  they 
are  drawn  in  an  oil-tempering  bath  and  the  tempera- 
ture gauged  by  a  thermometer.  In  this  way  absolute 


MISCELLANEOUS   WORK.  303 

uniformity  of  temper  may  be  obtained,  which  is 
quite  impossible  where  tools  of  irregular  contour  or 
ununiformity  of  size  are  treated  by  the  color  method. 

If  the  mill  must  be  tempered  to  color,  a  very  com- 
mon method  consists  in  drawing  on  a  heated  plug. 
While  this  gives  good  results  in  cases  where  extreme 
care  is  exercised,  it  is  a  source  of  a  great  deal  of 
trouble  at  times,  especially  in  the  case  of  large  mills 
and  those  having  large  and  small  sections  adjacent 
to  one  another.  If  the  plug  is  to  be  used  the  mill 
should  have  several  teeth  brightened  on  their  backs. 
It  should  then  be  held  over  a  fire  and  heated  until 
lard  oil  placed  on  the  teeth  commences  to  smoke. 
The  mill  may  now  be  placed  on  the  plug  which  has 
been  heated  almost  to  a  red,  and  revolved.  The 
brightened  surfaces  should  be  closely  watched,  when 
they  show  a  light  straw  color  it  should  be  plunged 
into  warm  oil,  but  never  into  cold  water. 

Let  us  return  for  a  moment  to  the  subject  of  baths 
used  in  quenching  milling  cutters.  The  one  most 
commonly  used  is  clear,  cold  water.  Right  here  we 
may  get  into  trouble  as  extremely  cold  baths  should 
seldom  or  never  be  used  when  hardening  this  class 
of  tool.  There  are  few  cases  where  the  water  should 
be  below  60°  F.  and  many  cases  where  70°  F.  will 
give  better  results.  The  bath,  however,  should  be 
of  generous  proportions,  especially  if  it  has  no  means 
whereby  a  constant  supply  of  liquid  is  being  fed  into 
it.  If  it  is  provided  with  a  supply  pipe,  this  should 
have  a  steam  pipe  entering  it  so  that  the  incoming 
water  can  be  brought  to  the  proper  temperature 
before  coming  in  contact  with  the  work.  A  ther- 


FORGE-PRACTICE. 


:^^ W-ator 


mometer  should  be  kept  conveniently  near  in  order 
that  right  temperatures  can  be  readily  obtained. 
Both  the  inlet  and  steam  pipes  should  be  provided 
with  valves  in  order  that  the  desired  amount  of 
liquid  and  the  proper  temperature  may  be  had. 

If  brine  is  considered  the  proper  quenching  medium 
the  bath  may  be  provided  with  a  storage  tank  and 
pump  and  a  constant  supply  of  this  liquid  of  any 
desired  temperature  may  be  had.  If  oil  hardening 
steels  are  used  in  making  the  mills  a  bath  having  a 

constant  supply  of  oil  of  the 
proper  temperature  may  be 
used.  Both  the  oil  and  brine 
baths  are  illustrated  and 
described  under  "Baths." 

Many  hardeners  use  a  bath 
of  water  or  brine  with  an  inch 
or  two  of  oil  on  the  surface 
as  shown  in  Fig.  315.  The 
red-hot  steel  passing  through 
the  oil  takes  a  thin  coating  of 
oil  which  prevents  too  sud- 
den action  by  the  lighter  liquid  underneath.  This 
form  of  bath  has  been  used  by  the  writer  for  a  num- 
ber of  years  on  certain  classes  of  work,  especially 
where  the  teeth  of  mills  were  cut  with  a  sharp- 
pointed  cutter.  The  oil  lodging  in  these  sharp  cuts 
prevents  the  rapid  action  incident  to  a  lighter  fluid 
acting  directly  at  these  points. 

Thin  Cutters. — Screw  slotting  cutters,  slitting  saws 
and  other  forms  of  very  thin  cutters  are  hardened 
very  nicely  between  flat  plates.  These  plates  may 


FIG.  315. 


MISCELLANEOUS   WORK.  305 

be  so  arranged  that  when  the  cutter  is  placed  be- 
tween them  they  will  submerge  in  oil  or  water,  or 
in  the  case  of  medium  thin  cutters  the  faces  of  the 
plates  may  be  smeared  with  oil,  or  in  the  case  of 
very  thin  cutters  the  plates  alone  will  absorb  the 
heat  fast  enough  to  produce  desired  results.  Where 
but  a  few  cutters  are  hardened  at  a  time  ordinary 
bench  plates  of  convenient  size  may  be  used.  This, 
of  course,  necessitates  the  services  of  two  men,  the 
hardener  and  a  helper.  Where  the  work  is  done  in 
large  quantities  such  practice  would  prove  costly 
and  a  special  device  where  the  movable  plate  is 
operated  by  the  foot  may  be  employed,  thus  making 
it  possible  for  one  man  to  tend  to  the  heating  of  the 
cutters  and  to  operate  the  plate. 

Troubles. — In  an  experience  of  over  twenty  years 
in  looking  into  other  peoples'  troubles  the  writer  has 
found  that  as  many,  if  not  more,  difficulties  are 
encountered  by  hardeners  in  treating  milling  machine 
cutters,  as  any  class  of  cutting  tool.  Most  of  these 
troubles  are  directly  traceable  to  comparatively  few 
causes.  The  most  common  cause  is  ununiformity 
in  heating.  As  previously  stated,  a  piece  of  steel 
that  is  not  uniformly  heated  is  bound  to  cause  trouble 
when  it  contracts  in  the  operation  of  hardening.  If 
any  portion  of  a  piece  has  been  overheated  and  then 
allowed  to  cool  in  the  furnace  to  the  temperature  of 
the  balance  of  the  piece,  that  portion  has  the  same 
structure  internally  as  would  have  been  the  case 
had  it  been  hardened  at  that  heat,  and  on  account 
of  this  difference  of  grain  structure  cracks  are  liable 
to  result.  Improper  handling  when  in  the  bath  is 


306  FORGE-PRACTICE. 

more  common  than  is  generally  known.  In  order 
that  steel  may  harden  satisfactorily  it  is  necessary 
that  it  should  contract  uniformly.  This,  in  the  case 
of  cutters  of  irregular  shapes,  means  skillful  handling 
in  the  bath.  High  heats  are  a  source  of  more  or  less 
trouble,  but  not  so  frequently,  encountered  at  the 
present  time  as  a  few  years  ago  on  account  of  the 
better  knowledge  hardeners  have  of  the  effect  of 
high  heats  on  steel.  Underheating  is  often  found  to 
be  a  source  of  trouble  not  generally  considered  as  a 
piece  of  steel  may  be  hardened  so  that  it  will  be  file 
hard  and  yet  not  be  in  condition  to  cut  other  metals. 
While  steel  should  not  be  heated  any  higher  than  is 
necessary  to  produce  desired  results,  it  must  be 
brought  to  the  right  temperature  to  get  these  results. 
Draw  Broaches. — This  form  of  tool,  if  made  from 
straight  carbon  tool  steel  should  be  hardened  at  a 
temperature  that  insures  the  greatest  possible  tensile 
strength,  as  the  tendency  is  to  pull  apart  when  in 
use.  As  much  trouble  is  experienced  from  insuf- 
ficient chip  space  between  the  teeth,  as  from  im- 
proper hardening.  This  is  a  defect  over  which  the 
hardener  has  no  control,  and  ignorance  of  the  cause 
of  the  trouble  may  lead  to  constant  changes  in  meth- 
ods of  treatment  until  the  hardener  loses  confidence 
in  his  own  ability.  Very  many  forms  of  cutting 
tools  show  remarkable  ability  to  stand  up  and  retain 
a  keen  cutting  edge  when  pack  hardened,  but  draw 
broaches  to  be  used  for  heavy  cuts  do  not  stand  up  as 
well  as  when  heated  in  a  tube  and  plunged  in  a  light 
oil  to  which  has  been  added  a  small  amount  of  alum 
or  borax,  preferably  the  former.  Larger  broaches 


MISCELLANEOUS   WORK.  307 

are  usually  quenched  in  luke  warm  water  which 
has  a  thin  coating  of  light  oil  on  the  surface,  and  the 
temper  drawn  to  a  full  straw. 

Rivet  Sets. — The  excessive  strain  and  wear  to 
which  rivet  sets  are  subjected  renders  necessary  the 
exercise  of  extreme  care  in  heating  and  quenching, 
and  also  a  considerable  display  of  ingenuity,  at  times, 
to  determine  the  best  method  to  pursue  to  get  de- 
sired results. 

Experiments  are  many  times  desirable,  especially 
when  using  the  so-called  alloy  steels  to  determine  the 
exact    heat    treatment    necessary    to 
obtain    good    results.     Steel    makers' 
instructions     regarding     temperatures 
best  suited  to  desired  results  are  not 
always  to  be  relied  on  when  the  steel  is 
used  for  some  specific  purpose  entirely 
out   of  the  range  anticipated  by  the 
steel  maker.     The  writer  recalls  one 
particular  steel  that  was  used  for  rivet 
sets.      This  steel   when    hardened    at       FlG      6 
the    temperature     called     for    in    the 
instructions  on  the  bar  did  not  show  even  average 
results.     When  heated  150°  F.  higher,  or  to  1500°  F. 
it  gave  remarkable  results. 

When  quenching  it  is  advisable  to  rest  the  sets  on 
the  plain  end  and  send  a  stream  of  water  directly 
into  the  impression  as  shown  in  Fig.  316. 

Large  Rings. — When  heating  large  rings  and  sim- 
ilar pieces  for  hardening  it  is  necessary  to  have  a 
suitable  furnace  or  satisfactory  results  cannot  be 
obtained.  Fig.  3 1 7  shows  a  gas-burning  furnace  espe- 


3o8 


FORGE-PRACTICE. 


cially  designed  for  such  pieces.     This  furnace  being 
round  in  form  will  heat  a  round  piece  more  uniformly 


FIG.  317. 

than  one  rectangular  in  form  unless  extra  precautions 
are  taken  with  the  latter. 


MISCELLANEOUS   WORK.  309 

If  it  is  necessary  to  use  an  ordinary  case  hardening 
furnace  a  piece  of  sheet  steel,  or  sheet  iron  several 
inches  larger  each  way  than  the  piece  should  be 
placed  on  the  floor  of  the  furnace,  on  this  should  be 
several  pieces  of  iron  all  of  a  uniform  thickness,  for 
the  ring  to  rest  on.  After  being  placed  in  position 
the  ring  should  be  covered  with  granulated  charcoal 
or  with  a  mixture  of  charcoal  and  charred  leather 
and  gradually  heated  to  a  full  red.  The  heating 
must  not  be  carried  on  any  faster  than  is  consistent 
with  a  uniform  temperature  throughout  the  piece. 
If  many  pieces  of  a  size  are  to  be  hardened  it  is 
advisable  to  make  iron  boxes  several  inches  larger 
each  way  than  the  ring.  The  boxes  should  be  pro- 
vided with  covers.  In  the  bottom  of  each  box  place 
several  inches  of  granulated  charcoal;  on  this  place 
the  ring,  filling  the  box  with  the  packing  material. 
After  the  cover  is  in  position  the  box  may  be  placed 
in  the  furnace  and  the  ring  gradually  heated  to  the 
desired  temperature. 

As  the  red-hot  ring  would  go  out  of  shape  if  held 
in  any  but  a  horizontal  position,  and  as  all  portions 
are  desired  hard,  it  is  necessary  to  provide  a  special 
holder  for  use  in  dipping  in  the  bath.  This  holder 
should  be  so  designed  that  water  can  have  free  access 
to  all  portions  of  the  ring.  The  supporting  parts  of 
the  holder  should  be  worked  nearly  to  a  sharp  edge 
so  as  not  to  retard  the  action  of  the  water. 

The  bath  should  be  of  the  design  shown  in  Fij.  278 
having  jets  from  the  bottom  and  top  and  pipes  up 
the  sides  to  force  water  against  the  circumference 
of  the  ring.  When  the  piece  has  cooled  throughout 


310  FORGE-PRACTICE. 

to  the  temperature  of  the  water  it  may  be  removed 
from  the  bath  and  immediately  heated  to  remove 
hardening  strains.  While  this  heating  is  going  on 
the  piece  may  be  brightened  and  the  temper  drawn 
the  desired  amount. 

Spring  Threading  Dies. — Spring  threading  dies, 
hollow  mills  and  similar  tools  having  holes  running 
through  them,  or  part  way  through  them,  and  whose 
cutting  portions  are  on  the  end  should  be  quenched 
in  a  bath  of  brine  with  the  cutting  end  up  to  allow  the 
steam  to  escape  readily.  They  should  be  worked 
up  and  down  in  the  bath  to  force  the  liquid  to  all 
portions  of  the  hole. 

For  most  work  the  cutting  portions  should  be 
drawn  to  a  full  straw  color  (460°  F.)  and  the  balance 
drawn  to  a  blue. 

Spring  Tempering. — Such  articles  as  springs,  screw 
drivers,  etc.,  are  hardened  and  tempered  in  such  a 
manner  that  if  bent  they  will  return  to  their  original 
shape  when  the  strain  is  removed. 

Small  articles  are  usually  hardened  in  oil  prepara- 
tory to  spring  tempering,  as  water  would  cause 
brittleness  that  could  not  be  done  away  with  in  the 
tempering  process.  Medium-sized  pieces  are  many 
times  hardened  in  warm,  or  even  hot  water,  while 
extra  large  ones  may  be  hardened  in  warm  or  luke- 
warm water. 

The  object  of  the  hardening  process  in  spring 
tempering  is  not  to  produce  actual  hardness,  but 
stiffness,  and  the  less  brittleness  produced  by  the 
operation,  the  better.  Steel  hardened  in  oil  is  much 
tougher  than  if  hardened  in  water  and  it  is  advisable, 


MISCELLANEOUS  WORK.  311 

whenever  possible,  to  use  oil,  even  though  it  is  neces- 
sary to  add  some  substance  to  it. 

For  most  purposes  special  grades  of  spring  steel 
give  better  results  than  tool  steel.  A  good  grade  of 
open-hearth  steel  containing  from  .40  to  .80  per  cent 
carbon,  if  made  into  springs,  will  prove  more  satis- 
factory than  a  grade  of  tool  steel  costing  five  times 
as  much. 

In  the  selection  of  steel  for  springs  to  be  subjected 
to  but  little  strain  almost  any  good  grade  of  spring 
steel  will  answer.  If,  however,  it  is  to  be  subjected 
to  very  rough,  hard  usage  it  is  best  to  obtain  directly 
from  the  steel  maker  the  necessary  information 
regarding  the  exact  grade  needed  unless  the  user  has 
had  education  or  experience  that  enables  him  to 
rightly  decide  as  to  the  quality  needed. 

When  heating  for  hardening  employ  the  lowest 
heats  possible  consistent  with  good  results.  As 
spring  steel  contains  less  carbon  than  ordinary  tool 
steel  it  may  be  necessary  to  heat  it  a  trifle  hotter  to 
obtain  satisfactory  results.  This  should  always  be 
determined  by  experiment  before  going  ahead  with  a 
batch  of  work. 

The  nature  of  the  spring  must  determine  the  char- 
acter of  the  bath.  For  ordinary  purposes  sperm  oil 
works  well,  at  other  times  a  good  grade  of  lard  oil, 
cotton-seed  oil,  fish  oil  or  some  of  the  commercial 
hardening  oils  may  be  found  to  answer  the 
purpose. 

It  is  necessary  sometimes  to  add  certain  ingre- 
dients to  the  oil  to  obtain  desired  results.  The 
following  formula  is  used  by  a  manufacturer  who 


312  FORGE-PRACTICE. 

makes  large  quantities  of  springs  about  the  size  of 
ordinary  clock  springs: 

Sperm  oil 15  parts 

Beef  tallow 2  parts 

Resin i  part 

At  times  it  has  been  found  necessary  to  add  a  piece 
of  bee's  wax  to  the  above  to  prevent  a  granular  con- 
dition in  the  hardened  steel. 

Some  hardeners  use  turpentine  in  place  of  resin 
in  the  above  formula.  Its  use  is  not  to  be  advocated 
unless  extreme  care  is  exercised  as  it  is  highly  in- 
flammable and  serious  burns  may  result. 

Springs  should  never  be  heated  in  a  furnace  where 
oxidation  of  the  surface  takes  place,  as  this  oxidation 
may  assume  the  form  of  blisters  that  would  prevent 
the  contents  of  the  bath  coming  in  intimate  contact 
with  the  steel  at  those  portions,  and  would  result  in 
soft  spots  that  would  be  fatal  to  the  spring.  Resin  in 
the  bath  has  a  tendency  to  strike  any  ordinary  scale; 
but,  it  is  best  to  do  away,  as  far  as  possible,  with 
oxidation. 

Drawing  Temper. — If  but  a  few  springs  are  tem- 
pered at  a  time,  the  temper  may  be  drawn  by  heating 
until  tallow,  sperm  or  lard  oil  will  catch  fire  (flash) 
from  the  heat  in  the  steel.  To  determine  this  the 
spring  must  be  removed  from  the  fire  when  the  oil 
on  its  surface  starts  to  burn ;  if  it  continues  to  burn 
when  away  from  the  heat  of  the  fire  it  has  absorbed 
sufficient  heat,  if  not,  it  should  again  be  heated. 
Very  heavy  springs  may  have  the  oil  flashed  off  two 
or  even  three  times.  The  method  just  described 


MISCELLANEOUS   WORK.  313 

answers  when  the  steel  from  which  the  springs  are 
made  contains  a  fairly  high  percentage  of 
carbon. 

When  low-carbon  spring  steels  are  used  flashing 
cannot  be  resorted  to  as  it  leaves  the  springs  too  soft. 
In  such  cases  they  must  be  brightened  and  the  tem- 
per drawn  by  color.  The  exact  temper  color  can- 
not be  stated  arbitrarily  as  the  carbon  content  of 
the  steel  must  determine  this,  but  usually  it  ranges 
from  a  light  blue  to  a  dark  blue. 

When  work  is  done  in  quantities  it  is  always  best 
to  place  the  pieces  in  a  perforated  pail  which  is 
immersed  in  a  kettle  of  oil  over  a  fire  and  the  whole 
heated  until  the  right  temperature  is  reached. 
This  is  determined  by  means  of  a  thermometer. 
The  kettle  should  be  so  designed  that  a  cover  may  be 
placed  on  it  in  case  the  oil  catches  fire.  The  cover 
should  be  provided  with  a  long  handle,  in  order  that 
the  operator  will  not  be  burned  when  putting  it  in 
position.  It  should  be  made  high  enough  to  receive 
the  thermometer. 

It  is  advisable  to  leave  the  thermometer  in  the 
oil  and  allow  it  to  cool  with  the  oil.  If  it  is  neces- 
sary to  remove  the  thermometer  place  it  where  no 
draft  of  air  can  strike  it,  as  sudden  changes  of  tem- 
perature will  cause  the  glass  to  crack. 

Certain  forms  of  springs  are  heated  in  a  crucible 
of  melted  salt  for  hardening,  while  others  are  heated 
in  melted  glass.  These  provide  excellent  mediums 
for  uniformly  heating  springs  of  unequal  size  in  the 
various  portions. 

Heavy  springs  and  screw  drivers  are  tempered  at 


314  FORGE-PRACTICE. 

times  by  heating  in  the  fire  and  gauging  the  tempera- 
ture by  drawing  a  hard- wood  stick  or  a  hammer 
handle  across  a  corner  of  the  piece.  If  the  shaving 
removed  catches  fire  from  the  heat  in  the  steel  fur- 
ther heating  is  unnecessary.  If  there  is  a  liability  of 
the  piece  being  heated  too  much,  it  may  be  checked 
when  it  reaches  the  proper  temperature  by  plunging 
in  warm  oil. 

Second  Blue. — Springs  made  from  high-carbon  spring 
steel  and  tool  steel  are  sometimes  tempered  to  the 
second  blue.  This  is  done  where  the  rich  blue 
appearance  is  desirable  when  the  springs  are  located 
where  they  can  be  seen  on  exhibition  machines.  To 
accomplish  this  the  springs  are  polished  after  hard- 
ening, placed  in  a  pan  of  sand  and  shaken  over  a 
fire  until  the  proper  temper  color  appears.  The 
colors  will  show  as  stated  in  the  Temper  Color  Chart. 
After  the  colors  have  all  appeared  as  set  forth  the 
surface  assumes  a  gray  color  followed  by  a  blue 
which  is  called  the  second  blue.  When  the  second 
blue  appears  the  spring  should  be  immersed  in  warm 
oil  to  prevent  the  temper  going  too  far. 
,  The  writer  has  found  prolonged  heats  to  be  a 
common  cause  of  poor  results  in  hardening  springs. 
Such  heats  not  only  tend  to  oxidation  but  also 
weaken  the  steel.  The  practice  of  raising  a  furnace 
to  a  given  temperature  and  then  allowing  the  springs 
to  soak  in  the  fire  until  they  reach  the  furnace  tem- 
perature cannot  be  condemned  too  severely.  Any- 
'one  can  convince  themselves  of  the  truth  of  this 
assertion  by  heating  two  springs,  one  by  a  method 
that  insures  uniform  temperature  as  rapidly  applied 


MISCELLANEOUS  WORK.  315 

as  possible,  and  the  other  by  soaking,  then  testing 
in  comparison  with  one  another. 

A  manufacturing  concern  condemned  some  0.60 
per  cent  carbon  spring  steel  being  under  the  im- 
pression that  it  would  not  harden.  Investigation 
showed  that  this  steel  was  heated  in  a  furnace  with  a 
temperature  of  nearly  1500°  F.,  the  springs  being 
left  in  until  they  were  of  the  same  temperature  as 
the  furnace.  Another  batch  heated  quite  rapidly 
and  only  exposed  to  the  heat  for  about  one-quarter 
of  the  customary  length  of  time  and  quenched  at  a 
lower  temperature  hardened  perfectly.  When  the 
temper  was  drawn  these  springs  met  every  demand 
in  the  testing.  As  these  springs  had  to  stand  very 
heavy  strains  the  tests  were  correspondingly  severe. 

As  in  annealing  prolonged  heats  in  hardening 
should  always  be  avoided  as  they  change  the  struc- 
ture of  the  steel  and  render  it  unfit  for  use. 

Drop  Forging  Dies. — Drop  forging  dies,  when 
made  for  general  work,  tax  the  ingenuity  and 
resourcefulness  of  the  hardener  to  a  degree  not  experi- 
enced with  any  other  class  of  tool.  As  they  must  be 
treated  so  as  to  produce  a  hard  face  and  a  depth  of 
penetration  sufficient  to  prevent  sinking  when  in  use 
the  problem  becomes  difficult  in  proportion  to  the 
intricacy  of  the  design  of  the  impression  and  the 
resistance  of  the  stock  to  be  forged.  The  producing 
of  the  necessary  hardness  and  penetration  without 
warping  the  die  complicates  the  problem.  Forging 
dies  are  of  two  general  classes,  namely  hot  forging 
dies  and  cold  dropping  dies.  The  former  in  shops 
doing  general  jobbing  work  are  generally  made  from 


316  FORGE-PRACTICE. 

open  hearth  steel  containing  0.60  to  0.80  per  cent 
carbon.  In  other  plants  they  are  made  from  cru- 
cible steel  containing  about  the  same  proportion 
of  carbon. 

Cold  dropping  dies  are  usually  made  from  crucible 
steel  containing  a  higher  percentage  of  carbon  in 
order  to  obtain  a  deeper  penetration  and  a  stiffer 
backing  to  the  bottom  of  the  impression  as  the  ten- 
dency to  sink  is  greater  where  cold  metal  is  struck. 
All  portions  of  a  die  block  that  are  to  be  machined 
should  first  be  rough  machined  then  thoroughly 
annealed  before  the  impression  is  finished  and  the 
tang  machined  to  size.  This  annealing  heat  should 
be  about  50°  F.  higher  than  the  heat  employed  in 
hardening. 

In  shops  where  the  volume  of  business  warrants 
the  outlay  continuous  furnaces  are  used  in  heating 
the  block  for  hardening.  These  furnaces  are  so 
designed  that  the  portion  where  the  die  enters  is 
not  very  hot,  while  the  portion  at  the  opposite  end 
and  where  the  die  leaves  the  furnace  is  of  the  tem- 
perature the  die  is  to  be  heated.  The  use  of  this 
furnace,  of  course,  insures  ideal  conditions.  Such 
furnaces,  however,  are  not  in  general  use  and  the 
hardener  in  the  average  plant  finds  it  necessary  to 
produce  satisfactory  results  by  the  use  of  an  ordinary 
furnace.  This  can  be  done  by  the  exercise  of  ingenu- 
ity and  extreme  care.  When  possible  the  die  should 
be  placed  in  the  furnace  before  it  is  heated  very 
much  and  the  temperature  raised  gradually  to  pre- 
vent overheating  of  the  edges  and  corners. 

Dies  should  be  placed  in  shallow  boxes  with  the 


MISCELLANEOUS   WORK. 


317 


face  embedded  in  charred  leather,  or  animal  char- 
coal. To  accomplish  this  a  layer  of  one  of  these 
materials  about  2"  deep  should  be  placed  on  the 
bottom  of  the  box  and  the  face  of  the  die  laid  on 
this.  The  box  should  be  filled  with  the  packing 
material  extending  up  at  least  i"  beyond  the  depth 
of  the  impression.  Where  a  general  line  of  work  is 
done  it  is  necessary  to  have  boxes  of  various  sizes 
and  depths  to  satisfactorily  accomplish  the  desired 
results.  The  writer  has  advocated  for  years  filling 


FIG.  318. 

in  the  sides  of  the  tang  with  fire  clay  dough  as  shown 
in  Fig.  318,  and  placing  a  layer  of  the  same  on  top  of 
the  tang,  also,  as  shown.  This  prevents  the  hot 
gases  acting  directly  on  the  steel  at  these  portions. 
Many  experienced  hardeners  do  not  consider  this 
necessary,  but  results  have  proven  this  precaution 
to  be  of  value  entirely  out  of  proportion  to  the 
expense  involved,  which  is  slight.  The  furnace 
should  be  heated  gradually,  and  at  no  time  should 
the  temperature  be  allowed  to  exceed  the  tempera- 
ture to  which  the  die  is  to  be  heated,  or  some  portion 
will  become  overheated  and  cracks  will  result. 


FORGE-PRACTICE. 


In  order  to  successfully  harden  dies  of  this  char- 
acter a  bath  adapted  to  the  work  must  be  used. 
It  is  folly  to  attempt  to  obtain  good  results  unless 
a  plentiful  supply  of  water  that  can  be  projected 
against  the  die  is  available.  A  form  of  bath  that 
gives  excellent  results  is  shown  in  Fig.  319.  It  will 
be  noticed  that  the  overflow  pipe  is  telescoped  in 
order  that  any  desired  level  of  water  may  be  main- 
tained in  the  bath  as  this  should  be  somewhat  above 


FIG.  319. 

the  deepest  part  of  the  impression  when  the  die  is 
face  down  in  the  bath. 

In  some  shops  it  is  customary  to  partially  harden 
the  tang  before  hardening  the  face.  This  tends  to 
prevent  the  die  from  springing  when  the  irregular 
surface  of  the  face  is  hardened  and  is  done  by  placing 
the  die  on  the  supporting  wires  in  the  bath  with  the 
tang  down,  then  opening  the  valve  in  the  supply 
pipe  and  allowing  the  water  to  play  against  the  tang. 
The  overflow  pipe  should  be  adjusted  so  that  the 
contents  of  the  bath  will  come  about  i"  up  the  body 


MISCELLANEOUS   WORK.  319 

of  the  die.  The  water  should  be  allowed  to  play 
against  the  tang  until  the  red  has  disappeared  from 
the  portion  under  water,  then  the  position  of  the  die 
is  reversed  and  the  flow  of  water  is  allowed  to  come 
against  the  face.  In  the  meantime  water  should  be 
poured  from  a  dipper  or  some  convenient  retainer 
onto  the  tang  to  keep  it  from  drawing  back  until  the 
surface  of  the  face  is  below  a  red.  When  the  face 
has  lost  every  trace  of  red  cease  turning  water  on  the 
tang  and  allow  the  red  in  the  body  of  the  die  to  work 
back  through  the  tang.  When  the  die  has  cooled  to 
the  temperature  of  the  bath  it  may  be  removed  and 
heated  to  remove  hardening  strains.  There  are 
several  methods  of  doing  this.  One  method  consists 
in  placing  in  a  continuous  furnace  timing  the  travel 
of  the  die  so  that  it  will  reach  a  temperature  of  250° 
or  300°  F.  as  it  comes  out.  It  may  then  be  taken 
to  the  tempering  fire  and  the  heating  process  con- 
tinued until  the  temper  is  drawn  the  right  amount, 
if  it  is  necessary  to  temper  it  further  than  removing 
strains.  Another  method  consists  in  taking  directly 
from  the  bath  to  the  tempering  fire  and  relieving 
strains  there.  This  is  an  uncertain  method  as  the 
die,  unless  turned  frequently,  is  not  heated  uniformly 
and  if  the  heat  enters  one  portion  while  the  balance 
of  the  block  is  cold  and  unyielding  it  is  very  apt  to 
break. 

A  method  employed  with  very  good  results  in  a 
number  of  hardening  plants  is  to  place  the  die  in  a 
steam  box  on  wire  rods.  When  the  box  is  closed 
steam  is  turned  on  and  the  die  is  gradually  brought 
to  a  temperature  of  212°  F. 


320  FORGE-PRACTICE. 

Another  method  is  to  have  a  tub  of  water  with  a 
steam  pipe  entering  at  some  convenient  point.  The 
die  is  placed  in  the  water,  the  steam  turned  on,  and 
everything  brought  to  the  boiling  point.  The  boil- 
ing is  kept  up  until  the  die  is  uniformly  heated. 
It  is  a  mistake  to  immerse  dies  of  intricate  design,  or 
with  projecting  portions  from  the  face  directly  into 
boiling  water  as  is  sometimes  done,  as  the  slender 
portions  when  subjected  to  the  high  temperature 
expand  faster  than  the  balance  of  the  piece  and,  as  a 
result,  are  cracked  or  broken  off. 

When  hardening  dies  having  projections  from  the 
face,  or  which  have  delicate  portions  that  would  be 
liable  to  crack  from  the  unequal  contraction  in  the 
bath,  it  is  a  good  plan  to  cover  such  portions  with 
heavy  oil,  or  soap  just  before  immersing  in  the  hard- 
ening tank,  making  sure  that  there  is  a  generous  sup- 
ply of  the  substance  at  the  point  where  the  pro- 
jection joins  the  block.  This  will  retard  the  harden- 
ing at  these  points  thus  producing  a  more  uniform 
contraction.  The  water  from  the  supply  pipe  will 
wash  the  oil  or  soap  away  in  time  to  produce  suffi- 
cient hardness. 

A  method  of  quenching  employed  at  times  neces- 
sitates the  use  of  a  bath  of  the  design  shown  in  Fig. 
320.  In  this  case  the  die  is  lowered  into  the  bath 
until  it  rests  on  the  supporting  wires  with  the  tang 
well  back  toward  the  wall  of  the  tank.  The  jets  of 
water  playing  against  the  face  cools  it  very  nicely. 
In  the  case  of  dies  with  impressions  that  might  cause 
steam  to  pocket  in  them  this  form  of  bath  works 
well  as  the  steam  can  readily  escape. 


MISCELLANEOUS   WORK. 


32I 


FIG.  320. 

Another  method  is  to  lay  the  die  on  wires  in  a  tank 
from  which  the  water  can 
escape  without  coming  up 
around  the  die  and  from 
an  overhead  pipe  allow 
the  water  to  play  against 
the  face  which  is,  of 
course,  uppermost  as 
shown  in  Fig.  321. 

The  writer  is  inclined 
as  a  result  of  experience 
to  favor  the  first  method 
described  for  the  majority 

of  work.     Realizing,  how- 

FIG.  321. 
ever,  that  there  are  cases 

where  special  methods  of  quenching  must  be  resorted 
to  to  accomplish  certain  desired  results. 


322  FORGE-PRACTICE. 

Dies  from  some  of  the  alloy  steels  may  be  hardened 
in  oil ;  certain  of  the  steels  require  oil  hardening,  but 
in  such  cases  instructions  accompany  the  steel  stating 
the  exact  treatment  it  should  receive.  To  attempt 
to  describe  these  various  methods  would  be  a  need- 
less waste  of  time. 

When  worn  dies  made  from  straight  carbon  steel 
are  to  be  annealed  and  re-worked,  the  double  anneal- 
ing process  is  sometimes  resorted  to  with  good  re- 
sults. The  dies  are  first  heated  to  a  temperature 
75°  to  100°  F.  higher  than  the  hardening  heat  and 
allowed  to  cool.  They  are  then  heated  to  a  tem- 
perature slightly  lower  than  for  hardening.  Some 
hardeners  claim  that  dies  heated  in  this  way  are  less 
liable  to  go  to  pieces  when  hardened. 

Reworked  dies  should  have  sufficient  stock  re- 
removed  from  the  face  to  get  beneath  the  portions 
that  are  ruptured  as  a  result  of  the  compression  due 
to  the  constant  shocks  received  when  in  use. 

Causes  of  Trouble. — To  attempt  to  enumerate 
all  the  reasons  for  troubles  experienced  when  treat- 
ing steel  in  the  various  processes  of  heating  and 
cooling  would  be  an  almost  impossible  task,  but  to 
state  the  causes  commonly  experienced  is  a  much 
simpler  matter. 

In  the  shop  having  the  ordinary  furnace  capacity 
it  is  considered  advisable  to  purchase  all  tool  steel 
in  the  annealed  condition.  While  it  is  generally 
considered  that  the  steel  maker  knows  better  how  to 
anneal  the  product  of  his  mill  than  the  average 
man  in  a  heat-treating  plant,  he  cannot  anticipate 
everybody's  requirements.  As  a  result  mill  annealed 


MISCELLANEOUS  WORK.  323 

steel  may  or  may  not  be  in  the  best  possible  condi- 
tion for  hardening.  Then,  again,  a  considerable 
proportion  of  the  annealed  steel  purchased  from  a 
local  steel  warehouse  is  not  annealed  at  the  mill, 
but  by  some  local  concern  equipped  with  suitable 
furnaces.  The  writer  was  at  one  time  connected 
with  a  concern  that  regularly  annealed  about  two 
tons  of  tool  steel  a  day  for  local  steel  houses.  We 
could  not  anticipate  the  uses  to  which  the  steel  was 
to  be  put,  as  a  result  we  attempted  to  get  it  as  soft 
as  possible  without  in  any  way  injuring  the  metal. 

As  previously  stated  softness  is  not  the  only 
requirement.  There  are  many  other  things  to  be 
considered  but  some  of  these  cannot  be  anticipated 
until  one  knows  what  is  to  be  made  from  the  steel. 
Strains  cannot  be  successfully  removed  from  steel 
unless  it  is  blocked  out  somewhere  near  to  the  fin- 
ished shape.  This  is  especially  true  of  such  tools  as 
dies,  milling  cutters,  gauges,  etc.  As  a  result,  steel 
to  be  made  into  such  tools  should  be  carefully  an- 
nealed after  roughing  out,  even  though  it  has  been 
previously  annealed. 

Steel  that  has  been  over  annealed  is  in  no  condition 
for  hardening,  and  should  be  re-annealed  to  remove 
strains  and  to  refine  the  grain  previous  to  the  hard- 
ening heats.  Many  tools  are  ruined  in  the  process 
of  hardening,  because  the  steel  was  not  in  condition 
to  harden. 

As  commercial  bar  steel  has  a  decarbonized  sur- 
face occasioned  by  the  action  of  the  oxygen  in  the 
air  on  the  carbon  in  the  surface  of  steel  during  the 
process  of  rolling  and  hammering  in  the  steel  mill,  it 


324  FORGE-PRACTICE. 

is  necessary  to  remove  this  exterior  portion  for  a 
depth  sufficient  to  get  beneath  the  affected  metal. 
The  surfaces  of  forgings  are  decarbonized  in  the 
same  way.  In  order  to  get  good  results  when  hard- 
ening an  equal  amount  of  surface  stock  should  be 
removed  from  all  parts  of  the  piece  so  that  there  may 
not  be  left  at  any  point  metal  that  does  not  contain 
as  much  carbon  as  the  balance  of  the  piece  or  un- 
equal contraction  or  ununiformly  hardened  surfaces 
will  result.  It  is  always  better  to  remove  a  trifle 
more  surface  stock  than  not  quite  enough. 

Pieces  that  are  to  be  hardened  should  never  be 
straightened  when  cold.  If  a  piece  of  steel  that  is  to 
be  made  into  a  tool  is  bent,  heat  it  red  hot,  straighten, 
and  then  anneal.  If  steel  is  straightened  when  cold 
it  is  almost  sure  to  return  to  its  original  form  when 
heated  for  hardening. 

Overheating  is  a  common  cause  of  trouble.  The 
steel  is  weakened  because  the  interior  structure  is 
coarsened.  Overheating  also  has  a  tendency  to 
cause  steel  to  crack  in  a  direction  corresponding  to 
the  axis  of  the  piece. 

Ununiform  heating  of  steel,  when  hardening,  is 
the  most  common  source  of  trouble  experienced  by 
the  hardener,  and  manifests  itself  in  cracks,  or 
breaks,  the  direction  of  which  corresponds  to  the  line 
of  ununiformity  of  temperature. 

Long-continued  heating  (soaking)  renders  steel 
weak,  and  should  always  be  avoided.  On  the  other 
hand  heating  should  never  be  carried  on  more 
rapidly  than  is  consistent  with  a  uniform  tempera- 
ture throughout  the  piece. 


MISCELLANEOUS   WORK.  325 

Steel  as  it  comes  from  the  mill  sometimes  contains 
laps  or  seams.  If  either  of  these  defects  are  noticed 
the  steel  should  be  returned  to  the  party  from  whom 
it  was  purchased,  as  any  tools  made  from  such  stock 
are  almost  sure  to  go  to  pieces  when  hardened.  Such 
defects,  however,  are  not  common  at  the  present 
time,  as  the  inspection  of  ingots  and  bars  is  much 
more  thorough  than  it  was  at  one  time.  Such 
defects  may  be  so  located  that  they  cannot  be  seen 
until  the  piece  breaks.  If  the  steel  contained  a  seam 
its  walls  will  generally  have  a  much  different  appear- 
ance than  the  walls  of  a  crack  which  took  place  in  the 
bath.  In  the  latter  case  they  will  be  clean  except 
for  such  stains  as  the  contents  of  the  bath  may  have 
caused. 

Piping  is  a  defect  not  very  often  seen  in  com- 
mercial tool  steel.  When  the  ingot  of  steel  is  cooling 
in  the  mold  the  portion  near  the  center  remains 
fluid  much  longer  than  that  near  the  walls  of  the 
mold,  as  a  result  the  center  portion  contracts  more 
than  the  balance,  leaving  a  depression  at  the  center 
at  the  top  of  the  ingot.  This  defective  portion  is 
cut  away  (cropped).  At  times  the  defect  extends 
into  the  ingot  for  a  greater  distance  than  the  oper- 
ator is  aware  of,  and,  as  a  result,  ittis  not  all  re- 
moved. When  the  ingot  is  heated  for  rolling  the 
walls  of  these  defective  portions  become  oxidized 
and  do  not  weld  together,  the  defect  extending 
through  a  number  of  bars.  Ingots  and  bars  are 
subjected  to  a  very  rigid  inspection  in  all  first-class 
mills  and  if  " pipes"  are  discovered  the  bars  are  cut 
up  and  remelted.  No  reputable  steel  maker  would 


326  FORGE-PRACTICE. 

knowingly  allow  a  piped  bar  to  get  out  of  the  mill, 
yet  once  in  a  while  one  will  get  by.  When  discovered 
such  bars  should  be  returned,  as  any  tool  made  from 
them,  unless  the  piped  portion  was  cut  away,  is  almost 
sure  to  go  to  pieces  when  hardened.  The  writer 
knows  of  a  number  of  concerns  using  immense  quan- 
tities of  tool  steel  who  have  every  bar  that  is  to  be 
made  into  costly  tools  inspected  and  tested  before 
it  is  placed  in  the  stock  rack.  This  is  done  in  a  very 
systematic  manner.  A  thin  piece  is  cut  from  each 
end  of  the  bar  by  means  of  a  power  saw  and  the  sur- 
face is  carefully  inspected  under  a  powerful  micro- 
scope for  imperfections.  If  none  can  be  found  the 
pieces  are  hardened  and  then  broken  as  nearly  as 
possible  across  the  center.  The  fractured  surfaces 
are  then  inspected  under  the  microscope,  if  no 
defects  appear  one  or  more  of  the  pieces  are  tested 
with  a  "Shore  Scleroscope."  If  the  steel  shows  up 
all  right  under  the  inspection  and  test  the  bar  is 
marked  O.K.  and  placed  in  the  steel  rack. 

At  times  a  bar  of  steel  will  be  found  that  shows 
disintegration  of  some  element.  This  is  caused  by 
the  particles  of  the  element  separating  from  the  steel 
and  pocketing  at  some  point.  It  is  almost  impos- 
sible to  detect  this  defect  until  the  piece  is  machined, 
and  even  then  the  removal  of  material  may  not 
uncover  the  pocket,  and  the  piece  may  be  finished 
and  turned  over  to  the  hardener.  In  all  probability 
it  will  go  to  pieces  in  the  bath.  If  the  bar  from  which 
a  piece  containing  a  defect  of  this  kind  can  be  located 
it  should  be  condemned  and  returned  to  the  party 
from  whom  it  was  purchased.  Defects  of  this  kind 


MISCELLANEOUS   WORK.  327 

are  rare,  and  for  this  reason  but  little  understood 
by  the  men  engaged  in  heat-treating  steel. 

Hardened  pieces,  especially  those  that  are  round  or 
oval  in  form,  sometimes  show  soft  spots  on  the  sur- 
face. At  one  time  it  was  considered  by  many  hard- 
eners, and  by  a  number  of  writers  on  the  subject 
of  hardening,  to  be  almost,  or  quite  impossible  to 
avoid  this  trouble.  At  the  present  time  it  is  con- 
sidered unnecessary  to  have  such  spots.  They  are 
caused  by  scale  forming  on  the  surface  while  the 
piece  is  being  heated,  and  while  most  of  the  scale  will 
"strike"  (drop  off)  when  the  piece  is  placed  in  the 
bath  small  particles  may  remain  on  the  piece  and 
prevent,  or  retard  hardening.  This  can  be  pre- 
vented by  heating  in  a  manner  to  prevent  oxidation 
of  the  surface,  and  also  by  using  a  strong  salt  solu- 
tion in  a  bath  of  the  description  shown  in  Fig.  278. 
Another  cause  for  soft  spots  is  the  pocketing  of 
steam  at  certain  points.  The  bath  shown  in  Fig.  278 
will  prevent  the  steam  collecting  at  any  portion  and 
insure  uniformly  hardened  surfaces. 

It  is  sometimes  necessary  to  make  a  tool  from  a 
piece  ofisteel  that  is  not  of  sufficient  diameter  for 
the  purpose.  In  such  case  the  steel  is  given  the 
proper  diameter  by  upsetting.  If  such  practice  is 
necessary  select  steel  enough  smaller  than  finished 
size  so  that  the  process  of  upsetting  is  very  thorough. 
The  upsetting  should  be  accomplished  by  blows  suf- 
ficiently heavy  to  reach  to  the  center  of  the  piece,  or 
unsatisfactory  results  will  follow  when  the  piece  is 
hardened.  It  is  poor  practice  to  upset  a  portion  of  a 
piece  that  is  to  be  hardened  allover,  as  the  flow  of 


328  FORGE-PRACTICE. 

the  stock  occasioned  by  the  working  of  the  bar  in  the 
mill  will  be  in  one  direction,  while  that  occasioned  by 
the  upsetting  will  be  at  right  angles  to  the  first,  thus 
creating  the  worst  possible  condition  for  hardening. 
Unless  all  portions  of  a  piece  can  be  thoroughly 
upset  it  is  unwise  to  attempt  to  increase  its  diameter. 
As  a  rule  upsetting  a  piece  of  tool-steel  that  is  to  be 
hardened  is  not  advisable;  but,  where  it  must  be 
resorted  to  be  sure  that  the  precautions  mentioned 
are  closely  observed. 

Pack  Hardening. — The  term  Pack  Hardening  was 
applied  to  the  superficial  carburizing  of  tool  steel 
surfaces  about  twenty-five  years  ago  while  the 
writer  was  in  charge  of  a  heat-treating  department 
doing  a  large  jobbing  business.  We  were  hardening 
a  great  many  punch-press  dies  of  unusual  size  and 
complex  design,  milling  machine  cutters,  and  various 
other  tools. 

At  that  time  there  was  a  shortage  of  skilled  help 
versed  in  the  heat  treatment  of  steel.  The  volume 
of  business,  and  the  requirements  of  the  tools  we 
were  hardening  forced  us  to  experiment  along  lines 
that  would  enable  us  to  successfully  harden  tools 
that  were  made  from  steels  the  make  and  compo- 
sition of  which  we  were  many  times  ignorant  of. 

This  was  before  the  modern  oil-hardening  steels 
were  made,  or,  at  least,  generally  used.  We  rea- 
soned that  as  thin  pieces  of  steel  hardened  in  oil 
seldom  cracked  or  warped  to  any  extent,  it  would  be 
advisable  to  treat  ordinary  tool  steel  tools  so  that 
they  would  satisfactorily  harden  in  oil.  As  bone 
contains  a  considerable  percentage  of  phosphorus 


MISCELLANEOUS   WORK.  329 

and  this  element  is  highly  injurious  to  steel,  espe- 
cially steel  made  into  cutting  tools,  we  adopted 
leather  as  the  carburizing  agent.  An  experience  of  a 
quarter  of  a  century  has  failed  to  convince  me  that 
any  packing  material  that  I  have  experimented  with 
is  better  suited  to  this  work  than  a  good  grade  of 
charred  leather.  Although  several  satisfactory  com- 
mercial carburizers  have  been  analyzed  and  found  to 
contain  a  high  percentage  of  leather,  none  of  these 
worked  better  than  leather  alone. 

Although  this  method  is  used  very  extensively  in 
several  large  plants,  its  use  is  no  where  near  as  gen- 
eral as  it  should  be,  because  if  properly  done  breakage 
is  almost  entirely  eliminated,  and  warping  is  reduced 
to  the  minimum. 

High-carbon  as  well  as  low-carbon  steels  respond 
to  this  treatment,  although  if  the  steel  contains  more 
than  1.25  per  cent  carbon,  charred  hoofs,  or  a  mix- 
ture of  charred  hoofs  and  horns,  should  be  used 
instead  of  leather. 

An  argument  sometimes  advanced  against  this 
method  is  its  high  cost.  When  we  consider  that 
quite  a  number  of  tools  can  be  packed  in  a  box  and  a 
number  of  these  boxes  can  be  treated  at  a  time  it 
will  be  seen  that  the  actual  cost  is  in  this  way  con- 
siderably lessened.  Even  though  the  cost  were 
greater  its  use  is  to  be  advocated  when  we  consider 
that  dies  treated  by  this  method  will  last  many 
times  longer  than  those  hardened  by  the  ordinary 
fire  and  water  method.  Milling-machine  cutters  will 
be  found  to  run  considerably  faster  and  stand  up 
many  times  longer  between  grindings.  Taps  and 


330  FORGE-PRACTICE. 

dies  will  wear  much  longer,  and  other  classes  of  tools 
will  show  an  increased  efficiency  overbalancing  the 
extra  cost  of  treating  and  is  therefore  to  be  advocated. 

There  are  several  classes  of  tools  that,  under  cer- 
tain conditions,  do  not  prove  as  efficient  when  pack 
hardened.  For  instance,  draw  broaches  doing  ex- 
tremely heavy  work  in  proportion  to  their  diameter; 
slender  piercing  punches  used  on  stock  whose  thick- 
ness exceeds  the  diameter  of  the  punch  and  other 
tools  that  are  slender  in  cross-section  that  are  sub- 
jected to  excessive  tensile  or  crushing  strains,  but  the 
classes  of  tools  that  do  not  satisfactorily  respond  to 
this  treatment  are  few  in  comparison  to  those  that 
are  wonderfully  helped  by  it. 

Temperature. — The  temperature  to  be  employed 
should  be  determined  by  test  wires  and  pyrometer, 
and  should  rarely  exceed  the  critical  range  of  the 
steel  which  runs  from  1375°  to  1400°  F.  The  length 
of  time  the  pieces  should  be  held  at  the  red  heat 
depends  on  the  size  and  character  of  the  piece. 
Before  packing  in  the  box  each  piece  should  be  wired 
with  iron  binding  wire  for  use  in  drawing  from  the 
box  and  dipping  in  the  bath.  Packing  in  the  boxes 
is  carried  out  the  same  as  for  case-hardening  except 
that  charred  leather  is  used  in  place  of  the  other 
carburizing  materials. 

Time. — The  length  of  time  the  pieces  should  be  left 
in  the  box  after  reaching  the  critical  temperature 
depends  on  the  size,  and  character  of  the  tool.  Small 
taps  \"  to  i"  should  be  left  in  the  box  one-half  hour; 
those  i"  diameter  two  hours;  reamers  of  the  same 
size  fifteen  to  thirty  minutes  longer;  milling  machine 


MISCELLANEOUS  WORK.  33! 

cutters  from  two  to  four  hours  according  to  size  and 
the  use  to  which  they  are  to  be  put;  and  punch- 
press  dies  from  two  to  four  hours  according  to  thick- 
ness of  the  walls.  Swaging  dies  are  one  of  the  most 
pronounced  examples  of  the  advantages  of  pack 
hardening.  If  they  are  to  be  subjected  to  very  se- 
vere duty  the  heat  employed  should  range  from  30° 
to  50°  higher  than  for  milling  cutters,  that  is,  from 
1400°  to  1430°  F.  This  is  to  secure  a  deeper  pene- 
tration and  a  more  solid  backing  for  the  surface 
receiving  the  rough  usage.  Stay-bolt  taps  should 
be  packed  in  a  pipe,  never  in  a  box,  as  drawing  the 
red-hot  tap  through  the  packing  material  in  remov- 
ing it  from  the  box  would  be  sure  to  bend  it. 

Gauges. — Pack  hardening  provides  the  most  satis- 
factory method  of  hardening  gauges  of  all  kinds. 
It  also  makes  possible  the  use  of  lower  grades  of 
steel  than  would  be  possible  if  the  ordinary  methods 
were  employed.  Ring  gauges  and  other  forms  hav- 
ing holes  passing  through  them,  where  the  walls  of 
the  holes  are  to  be  subjected  to  wear,  should  be  hard- 
ened in  a  bath  having  a  jet  of  oil  projected  by  a 
pump,  the  jet  passing  through  the  hole  under  con- 
siderable pressure  forces  all  vapors  away  and  allows 
the  oil  free  access  to  the  surfaces  desired  hard.  If 
the  outer  portion  of  the  gauge  is  irregular  in  form 
so  that  there  is  a  heavier  wall  of  steel  at  one  side  of 
the  hole  than  the  other,  it  is  a  good  plan  to  encase 
it  in  fire  clay,  which  may  be  wired  on  to  prevent  it 
from  cracking,  and  breaking  away.  This  should  be 
done  before  the  gauge  is  placed  in  the  hardening  box 
and  may  be  removed  after  it  is  taken  from  the  bath. 


332 


FORGE-PRACTICE. 


This,  of  course,  leaves  the  outer  walls  soft,  and 
applies  only  to  pieces  where  the  walls  of  the  holes 
are  the  only  portions  desired  hard. 

TABLE   OF  APPROXIMATE   TEMPERATURES. 
FORGING  AND  HARDENING  CARBON  STEEL  TOOLS. 


Approximate 
Carbon  Content. 

Approximate 
Forging  Tempera- 
ature. 

Critical 
Range. 

Approximate 
Hardening 
Temperature. 

0.60  per  cent 

i6oo°-i8oo°F. 

1340  °-i  380°  F. 

1480°  F. 

o  .  70  per  cent 

i6oo°-i7oo°F. 

I340°-I375°F. 

1470°  F. 

0.80  per  cent 

i  600  °-  i  700°  F. 

I3400-I365°F. 

1465°  F. 

0.90  per  cent 

i6oo°-i65o°F. 

i340°-i36o°F. 

1460°  F. 

i  .  oo  per  cent 

1600°  F. 

i340°-i36o°F. 

1450°  F. 

i  .  10  per  cent 

1550°  F. 

i340°-i36o°F. 

1440°  F. 

1  .  20  per  cent 

i500°F. 

i340°-i36o°F. 

1425°  F. 

i  .  30  per  cent 

1500°  F. 

1  340°-  1  360°  F. 

1410°  F. 

i  .  40  per  cent 

1500°  F. 

i34o°-i36o°F. 

1400°  F. 

Case  Hardening. — In  the  process  of  case  hardening, 
a  hard  surface  is  produced  over  a  soft  center,  or  core. 
The  metals  commonly  treated  are  wrought  iron,  low- 
carbon  steel,  and  cast  iron. 

The  process  is  a  modification  of  the  cementation 
process  of  converting  wrought  iron  into  blister  steel 
and  differs  from  it  essentially  in  that  it  is  not  carried 
so  far.  In  the  cementation  process  the  carbon  is 
charged  to  the  center  of  the  iron,  while  in  case 
hardening  it  is  stopped  when  a  case  of  hardening 
steel  deep  enough  to  answer  the  purpose  is  pro- 
duced. 

The  proper  selection  of  stock  to  use  for  articles 
that  are  to  receive  this  treatment  should  be  given  a 
great  deal  more  consideration  than  is  generally  the 
case.  In  practice,  any  low-carbon  stock  whose 


MISCELLANEOUS   WORK.  333 

initial  cost  is  low,  and  which  machines  easily,  is 
many  times  selected  without  regard  as  to  whether 
the  core  is  strong  enough  to  resist  any  strains  it  may 
receive.  If  a  hard  surface  is  the  only  consideration, 
a  stock  low  in  carbon  is  selected,  usually  one  that 
does  not  contain  more  than  0.20  per  cent.  If 
bending,  breaking  or  other  strains  are  to  be  encoun- 
tered it  is  necessary  to  select  one  that  contains  a 
higher  percentage.  In  some  instances  it  is  neces- 
sary, in  order  to  obtain  needed  strength,  to  use  steel 
containing  0.60,  0.80  or  i  per  cent  carbon.  In  case 
the  high  carbons  are  used  it  is  advisable  in  most 
cases  to  avoid  water  baths  in  dipping,  using  instead, 
a  bath  of  oil.  In  this  way  a  very  hard  surface  with 
a  soft,  strong  core  is  obtained. 

Probably  no  one  branch  of  hardening  has  received 
more  intelligent  study  in  the  last  twenty-five  years 
than  the  one  under  consideration ;  yet,  in  some  shops, 
the  subject  is  given  no  thought  and,  as  a  result,  an 
inferior  article  is  being  turned  out,  which,  if  certain 
parts  were  properly  case  hardened,  would  be  a  satis- 
factory product. 

Quick  Case  Hardening. — It  is  necessary  at  times  to 
case  harden  a  few  small  screws,  or  other  small  articles, 
and  depth  of  penetration  is  not  a  factor  to  be  consid- 
ered. Under  such  circumstances  the  necessary  hard- 
ness may  be  produced  by  heating  the  pieces  to  a  red 
and  applying  a  small  amount  of  cyanide  of  potassium, 
re-heat  the  pieces  to  a  red  and  plunge  in  clean,  cold 
water.  The  depth  of  penetration  may  be  increased 
by  several  applications  of  the  cyanide,  reheating 
after  each  application.  Always  make  sure  that  the 


334  FORGE-PRACTICE. 

direct  blast  does  not  strike  the  pieces,  as  the  resulting 
oxidation  would  decarbonize  the  surface  and  undo 
what  is  attempted. 

If  colors  are  desired  it  will  be  necessary  to  polish 
the  surfaces  and  have  them  free  from  grease  of  any 
kind.  The  pieces  should  be  heated  in  a  tube,  or 
covered,  when  in  the  fire,  with  a  piece  of  sheet  iron 
to  protect  them  from  the  direct  action  of  the  flame. 
They  should  rest,  when  heating,  on  a  clean  surface, 
usually  a  piece  of  fire  brick  or  iron.  The  quality 
of  the  colored  surfaces  may  be  bettered  by  intro- 
ducing air  into  the  water  at  the  location  of  dipping. 
This  may  be  accomplished  by  taking  a  piece  of  J" 
pipe  and  placing  one  end  in  the  bath  3"  or  4"  below 
the  surface,  then  blowing  on  upper  end  and  passing 
the  pieces  through  the  air  bubbles  in  the  water. 

Yellow  prussiate  of  potash  was  formerly  used  quite 
extensively  in  quick  case  hardening  either  alone,  or 
in  a  mixture  of  2  parts  prussiate  of  potash,  i  part  sal- 
ammoniac  and  i  part  salt.  At  the  present  time  it  is 
nearly  impossible  to  get  the  potash.  There  are  sev- 
eral quick  case  hardening  compounds  on  the  market. 
Some  of  these  give  very  good  satisfaction,  most  of 
them  have  this  to  their  credit,  they  are  not  poison- 
ous, while  cyanide  of  potassium  is  a  violent  poison 
and  should  be  kept  under  lock  and  key  when  not 
in  use. 

Carburizers. — To  get  good  results  when  doing  case 
hardening  on  a  large  scale  one  must  understand  the 
selection  of  stock  from  which  articles  are  to  be  made, 
the  effect  of  different  carbonizing  materials,  and  the 
effect  of  different  temperatures  on  the  stock.  He 


MISCELLANEOUS   WORK.  335 

must  know  what  results  are  desired  in  the  finished 
product  and  how  to  obtain  these  results.  There  are 
a  number  of  carburizers  used  in  charging  carbon  into 
iron  and  steel.  Granulated  raw  bone  is  more  com- 
monly used  than  any  other  material.  It  comes  in 
several  different  sizes  of  granules.  The  coarser 
grades  are  used  for  long  runs,  while  the  finest  is  used 
for  short  exposures.  Raw  bone  is  rich  in  phosphorus, 
and  as  this  causes  brittleness  when  present  in  steel 
this  form  of  bone  should  not  be  used  for  articles 
that  are  to  be  subjected  to  shock  or  blow  unless  they 
are  of  a  form  that  insures  the  desired  strength. 

Charred  Bone. — Bone  that  is  burned  sufficiently  to 
remove  the  phosphorus  and  grease  may  be  procured 
commercially,  or  it  may  be  charred  in  the  hardening 
furnace  by  filling  hardening  boxes  with  raw  bone, 
placing  the  covers  in  position  and  setting  the  boxes 
in  the  furnace  at  the  end  of  the  day  when  the  fur- 
nace has  been  run  for  several  hours.  At  the  time  of 
placing  the  boxes  in  the  furnace  the  fire  should  be 
shut  off  as  there  will  be  sufficient  heat  in  the  walls 
of  the  furnace  to  char  the  bone.  However,  should 
the  walls  of  the  furnace  be  light  in  construction  and 
not  hold  the  heat  long  enough  to  accomplish  the 
desired  result,  the  fire  may  be  run  very  low  for  a 
time  then  shut  off.  The  boxes  may  be  left  in  until 
morning.  When  removed  the  material  is  ready  for 
use. 

Animal  Charcoal. — Thoroughly  burned,  specially 
treated  bone  known  as  animal  charcoal  may  be  pro- 
cured commercially  and  is  used  for  the  finer  grades 
of  work.  Another  form  of  burned  bone,  known  as 


336  FORGE-PRACTICE. 

hydrocarbonated  bone,  is  used  for  certain  fine  grades 
of  work.  This  is  animal  charcoal  treated  with  oils. 

Wood  Charcoal. — Hard-wood  charcoal  is  used  as  a 
carburizer  either  alone,  or  mixed  in  various  propor- 
tions with  other  carbonizing  materials  and  should  be 
granulated  before  using.  Granulated  charcoal  may 
be  procured  commercially,  or  it  may  be  granulated 
and  sorted  to  size  by  sifting.  To  do  this  econom- 
ically on  a  large  scale  special  grinding  and  sifting 
machines  should  be  used.  Wood  charcoal  is  not  a 
satisfactory  packing  material  when  the  work  is  to 
run  for  a  long  period. 

Leather. — Charred  leather  provides  the  very  best 
material  for  use  on  the  finer  grades  of  work.  As  it 
is  more  expensive  than  bone  it  is  not  used  when  bone 
will  answer  the  purpose.  It  may  be  procured  com- 
mercially but  should  never  be  bought  from  any  but 
dealers  whose  reliability  is  known,  as  there  is  a  ten- 
dency on  the  part  of  some  to  use  any  scrap  leather 
they  can  get. 

Leather  may  be  charred  in  the  shop  by  getting  the 
scraps  that  soles  and  heels  of  shoes  are  punched  from 
as  this  gives  a  heavy  scrap.  Old  belting  that  has 
passed  its  usefulness  is  also  used.  The  leather  should 
be  cut  in  3"  or  4"  pieces  and  packed  in  the  box  as 
was  explained  under  Charring  Bone.  Care  should 
be  exercised,  or  the  leather  will  be  charred  too  much. 
This  process  should  be  carried  on  only  long  enough 
to  char  the  leather  until  it  can  be  crushed  in  the  hand. 

Barium  Carbonate. — A  mixture  of  3  5  parts  barium 
carbonate  and  65  parts  granulated  wood  charcoal 
is  used  with  excellent  results  in  a  number  of  shops. 


MISCELLANEOUS   WORK.  337 

The  proportions  given  need  not  be  accurately  ob- 
served but  may  be  varied  to  meet  requirements. 

Mixtures. — Various  mixtures  of  carbonaceous  ma- 
terials are  used  in  packing  work.  Materials  that 
have  no  direct  action  on  the  steel  are  many  times 
used  with  the  direct-acting  cements.  Two  parts 
common  salt  added  to  8  parts  granulated  hard-wood 
charcoal  materially  increases  the  action  of  the  latter, 
or  the  salt  may  be  added  to  mixtures  containing  char- 
coal, with  good  results. 

Mixtures  for  Short  Runs. — Where  pieces  are  not 
to  be  run  for  a  great  length  of  time  the  following 
mixtures  may  be  used:  i.  Granulated  hard- wood 
charcoal,  6  parts;  lamp  black,  2  parts;  granulated 
charred  leather,  2  parts.  The  charcoal  and  leather 
should  be  ground  fine  or  the  lamp  black  will  settle 
to  the  bottom  of  the  mass.  2.  Finely  granulated 
raw  bone,  7  parts;  animal  charcoal,  2  parts;  pow- 
dered charred  leather,  i  part.  3.  Powdered  wood 
charcoal,  4  parts;  sawdust,  5  parts;  salt,  i  part. 
4.  Hydrocarbonated  bone,  i  part;  charred  leather, 
4  parts;  charcoal,  4  parts;  salt,  i  part. 

The  formulas  for  dozens  of  mixtures  could  be  given 
but  a  study  of  the  effects  of  the  various  ingredients 
used  will  enable  one  to  adapt  the  quantities,  and 
select  the  carburizers  to  meet  the  various  require- 
ments. It  should  be  borne  in  mind  that  raw  bone 
should  not  be  used  where  extreme  toughness  is 
necessary,  and  that  leather  is  a  safe  carburizer  for 
all  steel  containing  less  than  1.25  per  cent  carbon. 

The  Boxes. — Articles  to  be  case  hardened  are 
packed  in  boxes  or  tubes  completely  surrounding 


338 


FORGE-PRACTICE. 


each  piece  with  the  carbonizing  material.  Small 
pieces  and  those  that  are  long  and  slender,  especially 
the  latter,  should  be  packed  in  tubes  as  more  uniform 
temperatures  can  be  obtained,  and  there  is  always 
danger  of  springing  long  slender  pieces  when  drawing 
them  through  the  packing  material  in  a  box  when  they 
are  red  hot.  As  such  pieces  must  be  dipped  vertically 
in  the  bath  they  canot  be  dumped  into  the  bath, 
but  must  be  handled  individually.  The  tubes  may 
be  pieces  of  iron  pipe  having  one  end  closed  tightly 
by  means  of  a  cap,  or  a  plug  may  be  driven  in  and 
securely  pinned  in  place.  When  the  tube  is  filled, 


FIG.  322. 

the  opposite  end  may  be  closed  by  a  loosely  fitting 
plug  which  sets  below  the  end  of  the  tube,  giving 
room  for  the  fire  clay  used  in  sealing  (luting)  as 
shown  in  Fig.  322. 

Boxes  of  various  sizes  and  shapes,  made  from  one 
of  a  number  of  materials  may  be  used.  Those  to  be 
used  for  small  work  should  themselves  be  small  in 
order  that  the  pieces  near  the  center  may  be  heated 
to  a  red  nearly  as  soon  as  those  nearer  the  walls. 
Boxes  that  are  larger  in  size  give  best  results  if  rect- 
angular in  form.  At  times  the  shape  of  the  piece 
necessitates  the  use  of  a  square  box.  Round  boxes 
work  well  for  small  pieces  but  are  not  so  easily 


MISCELLANEOUS    WORK. 


339 


handled  as  other  forms;  small,  round  boxes,  however, 
are  very  desirable  at  times. 

The  box  used  more  than  any  other  is  rectangular  in 
form  and  has  ribs  at  its  upper  edge  as  shown  in  Fig. 
323.  These  not  only  provide  a  means  of  handling 


FIG.  323. 


0 

1 

u 

o 

Design  of  Case  Hardening  Box  Used  in  some  Plants. 

with  the  grappling  iron,  or  dumping  fork,  as  it  is 
many  times  called,  but  tends  to  keep  the  boxes  from 
warping.  Round  boxes  are  generally  handled  with 
special  tongs  made  to  fit  the  box. 

The  material  used  in  making  boxes  may  be  sheet 


340  FORGE-PRACTICE. 

iron,  low-carbon  sheet  steel,  malleable  cast  iron,  or 
gray  cast  iron.  Boxes  made  from  sheet  iron  and 
sheet  steel  will  last  much  longer  than  those  made 
from  the  other  materials  mentioned,  while  malleable 
iron  is  more  durable  than  gray  iron.  The  number  of 
gray  cast-iron  boxes  in  use  in  hardening  plants  prob- 
ably exceeds  all  the  others,  as  they  are  more  cheaply 
and  readily  obtained.  However,  where  very  high 
heats  are  to  be  used,  cast  iron  is  relatively  short  lived. 

Time. — The  length  of  time  any  article  should  be 
exposed  to  the  carburizing  effects  of  the  material 
in  which  it  is  packed  depends  on  the  depth  of  pene- 
tration desired.  It  should  be  borne  in  mind  that 
iron  and  steel  do  not  commence  to  absorb  carbon 
until  nearly,  or  quite  red  hot.  Many  authorities 
claim  that  carbon  penetrates  iron  at  the  rate  of  J" 
in  twenty-four  hours  and  that  this  rate  is  fairly 
constant.  The  character  of  the  metal  being  charged, 
and  the  temperature  to  which  it  is  raised  has  consid- 
erable to  do  with  the  rate  of  penetration,  but  as  a 
basis  on  which  to  calculate  time  of  exposure,  it  is 
safe  to  consider  the  rate  mentioned,  making  due 
allowance  for  conditions. 

Small  Pieces. — When  packing  small  pieces  for  car- 
burizing it  is  advisable  to  use  small  boxes.  First, 
place  a  layer  of  packing  material  i"  or  ij"  deep  in 
the  bottom,  on  this  a  layer  of  work,  making  sure  that 
they  are  i"  from  the  walls  of  the  box  and  \"  to  J" 
from  one  another,  on  this  spread  a  layer  of  packing 
material,  then  one  of  work  and  so  continue  until  the 
box  is  filled  to  within  \\"  of  the  top.  After  each 
layer  of  packing  material  is  laid,  tamp  lightly  with  a 


MISCELLANEOUS  WORK.  34! 

block  of  wood.  There  should  be  a  layer  of  packing 
material  at  least  i"  thick  between  the  top  layer  of 
work  and  the  cover.  After  placing  the  cover  in 
position,  seal  the  space  between"  it  and  the  box  with 
fire  clay  mixed  with  water  to  the  consistency  of 
dough.  This  sealing,  or  luting,  as  it  is  many  times 
called,  should  be  allowed  to  dry  before  placing  in  a 
furnace. 

The  cover  should  have  five  or  six  \"  holes  drilled 
near  the  center.  After  placing  in  position  -£§"  wires 
should  be  run  through  these  to  the  bottom  of  the  box. 
These  wires  should  project  i"  above  the  top,  and 
should  be  sealed  with  fire  clay  to  prevent  the  escape 
of  gas.  These  are  known  as  test  wires  and  are  used 
to  determine  when  the  contents  of  the  box  are  red 
hot  to  the  center. 

Marking  Boxes. — Where  boxes  of  work  requiring 
different  time  exposures  are  to  be  heated  in  a  fur- 
nace, it  is  necessary  to  mark  the  boxes  so  that  they 
can  be  easily  distinguished.  This  may  be  done  by 
numbering  each  box  with  common  white  marking 
crayon.  These  marks  can  be  easily  seen  when  the 
boxes  are  red  hot.  The  boxes  requiring  the  longer 
exposures  should  be  placed  at  the  back  of  the  fur- 
nace. 

Testing. — When,  in  the  judgment  of  the  furnace- 
man,  a  box  has  been  exposed  long  enough  to  be 
heated  to  a  red,  one  of  the  test  wires  should  be  drawn 
by  means  of  long  tongs  and  examined.  If  it  is  red, 
the  time  should  be  noted  and  recorded  on  a  tally 
sheet,  or  slate,  together  with  the  number  of  the  box, 
what  it  contains,  time  it  should  be  removed  from  the 


342 


FORGE-PRACTICE. 


furnace,  highest  temperature  it  received  and  any 
other  facts  those  in  charge  think  best  to  keep. 
Below  is  a  sample  tally  sheet : 


Box  No. 

Contents. 

Furnace  No.  i.     Date,  May  6,  1918. 

Red  Hot. 

Remove. 

Highest 
Pyrometer 
Reading. 

I 
2 
3 

4 

Links  

10.  IO 
IO.25 
IO.3O 
10.50 

Furn 

10-45 
11.25 
11.30 
2.50 

ace  Operator, 

1450 
1450 
1455 
1470 

John  Smith. 

Binders  
Binders  
Bolts 

The  above  is  an  abbreviation  of  a  form  of  tally  sheet 
used  in  several  factories.  It  may  be  varied  to  meet 
requirements.  There  are  a  number  of  advantages 
derived  from  the  use  of  a  standard  tally  sheet. 
They  enable  those  in  charge  to  keep  closely  in  touch 
with  the  treatment  each  box  receives.  If  the 
results  show  that  the  pieces  were  not  given  the  proper 
temperature  or  time  exposure,  note  may  be  made  of 
the  fact,  and  the  practice  varied  with  the  next  batch. 
It  obviates  difficulties  that  arise  when  the  oper- 
ator's memory  is  relied  on  as  to  what  is  in  a  given 
box,  when  it  should  be  removed  from  the  furnace, 
and  also  tends  to  cultivate  carefulness  on  the  part 
of  the  operator. 

The  man  in  charge  of  the  heat-treating  depart- 
ment should  be  able  to  differentiate  between  work 
not  requiring  much  care,  and  that  requiring  the 
utmost  care  and  attention.  For  instance,  a  batch 
of  ordinary  machine  nuts  and  several  long,  slender 
shafts,  or  spindles  may  be  received  at  the  same  time. 


MISCELLANEOUS   WORK.  343 

The  nuts  may  be  packed  in  raw  bone  and  run  at 
fairly  high  heats,  while  the  spindles  should  be 
packed  in  tubes  with  charred  bone,  leather,  or  some 
mixture  that  will  not  give  off  phosphorus,  run  at  a 
low  temperature,  and  will  probably  require  a  def- 
inite time  exposure. 

The  Quenching  Bath. — The  design  and  contents 
of  the  hardening  bath  do  not  receive  the  attention 
they  should  in  some  shops.  A  batch  of  work  may 
be  packed  all  right,  receive  the  proper  time  exposure 
and  temperature  and  yet  not  give  desired  results, 
because  the  quenching  bath  was  not  deep  enough, 
or  had  no  means  of  separating  the  pieces  from  one 
another,  or  the  liquid  was  not  what  it  should  have 
been.  When  the  character  of  the  work  is  such  that 
a  barrel  of  water  that  is  provided  with  no  means  of 
agitation  will  produce  desired  results,  it  is  folly  to 
go  to  the  expense  of  rigging  up  an  expensive  bath, 
but  when  such  a  bath  is  necessary  to  get  definite 
conditions,  it  is  worse  than  folly  not  to  provide  it. 
The  tank  should  be  deep  enough  so  that  the  pieces 
will  cool  below  a  red  before  they  reach  the  bottom, 
if  the  box  of  work  is  dumped.  Where  the  pieces 
are  taken  singly  from  the  box  and  worked  around  in 
the  bath  until  cold  a  very  deep  bath  is  not  necessary. 
Large,  heavy  work  is  seldom  dumped. 

Tank  with  Separating  Wires. — In  cases  where  the 
work  is  dumped  directly  into  the  bath  from  the  box 
it  is  well  to  provide  some  means  of  separating  the 
pieces  or  ununiform  results  will  follow.  To  effect 
this,  wires  may  be  provided  as  shown  in  Fig.  279, 
making  sure  that  no  two  consecutive  rows  of  wires 


344  FORGE-PRACTICE. 

are  directly  in  line.  By  this  arrangement  the  work 
is  not  only  separated  but  is  turned  over  and  over  as 
it  bounds  from  one  wire  to  another  and  descends. 
The  bottom  of  the  tray  (a)  should  be  of  wire  netting 
or  thoroughly  perforated  sheet  metal  in  order  that 
the  water  may  circulate  freely  about  the  work,  and 
should  be  in  the  form  of  a  tray.  It  should  be  pro- 
vided with  handles  to  facilitate  its  removal.  Directly 
under  this  should  be  a  pan  (6)  also  provided  with 
handles  to  receive  the  packing  materials. 

If  bone  is  the  carburizer  used,  it  may  be  removed 
from  the  pan  and  dried  on  top  of  the  furnace,  or  in 
some  convenient  way  and  used  for  work  such  as 
screws,  etc.,  that  do  not  require  a  strong  material. 
For  certain  classes  of  work  it  may  be  used  in  con- 
nection with  fresh  bone,  in  proportions  varying 
according  to  the  requirements  of  the  pieces. 

This  bath  should  be  provided  with  a  supply  pipe 
as  shown,  and  also  with  an  overflow  pipe.  It  is  well 
to  arrange  a  hood  over  most  baths  where  work  is 
dumped.  This  hood  should  have  a  pipe  running 
into  a  chimney,  or  into  the  atmosphere  to  conduct 
the  steam,  smoke,  sparks,  etc.,  away,  as  they  are 
extremely  annoying  and  tend  to  injure  the  eyesight 
and  health  of  the  workmen. 

While  shafts,  spindles,  small  axles  and  similar 
pieces  are  many  times  dipped  one  at  a  time  ver- 
tically, excellent  results,  in  many  instances,  follow 
the  use  of  a  bath  of  the  form  shown  in  Fig.  2  80  where 
inclined  shelves  are  provided  to  allow  the  pieces 
to  go  down  into  the  bath  with  a  rolling  motion. 
These  shelves  should  be  thoroughly  perforated  to 


MISCELLANEOUS   WORK. 


345 


allow  the  liquid  constant  contact  with  the  steel. 
This  is  a  modification  of  the  so-called  "Coffin" 
method  of  treating  car  axles  and,  as  a  rule,  pro- 
duces good  results. 

The  bath  shown  in  Fig.  278  having  perforated  pipes 
up  the  sides,  is  adapted  to  work  that  is  to  be  dipped 
rather  than  dumped.  For  certain  kinds  of  work  a 


bath  having  pipes  coming  in  from  the  sides  and  one 
or  more  from  the  bottom  is  desirable.  In  fact,  when 
the  work  is  done  in  quantities  that  warrant  it,  the 
bath  should  be  designed  to  give  the  best  possible 
results  with  the  pieces  being  hardened. 

Fig.  324  shows  a  bath  designed  for  colorcase  hard- 
ening which  has  an  air  pipe  entering  the  water- 


346  FORGE-PRACTICE. 

supply  pipe.  A  bath  of  this  description  should  be 
in  every  plant  where  color  work  is  done. 

Oil  Baths. — Where  oil  is  the  quenching  medium 
employed,  some  means  should  be  provided  for  cool- 
ing it,  because,  unless  used  in  large  bodies  it  becomes 
heated  quickly  and  uniform  results  cannot  be  ob- 
tained as  some  pieces  will  enter  the  bath  while  the 
oil  is  cold  and  the  balance  will  enter  while  it  is  at 
various  temperatures.  As  extremely  cold  oil  seldom 
works  well,  care  should  be  taken  in  planning  for  the 
cooling  coils.  In  a  bath  of  this  kind  the  oil  is 
usually  taken  from  the  top  and  pumped  through  the 
coils  as  shown  in  Fig.  277  and  returned  to  the  tank 
at  any  desired  part.  For  certain  work  the  supply 
should  enter  at  the  bottom ;  for  other  work  the  inlet 
should  be  at  one  or  more  sides,  or  pipes  may  be  pro- 
vided to  enter  at  a  number  of  places  and  furnished 
with  valves  so  that  the  entry  may  be  where  it  will 
work  best  for  the  individual  job. 

For  a  number  of  reasons  the  contents  of  the  hard- 
ening box  should  never  be  dumped  directly  into  the 
oil.  If  the  pieces  are  large,  or  of  intricate  design, 
they  should  be  removed  from  the  box  individually 
and  immersed  in  the  bath  by  means  of  tongs,  a  hook, 
or  wire  and  worked  around  until  cooled  considerably 
below  a  red  when  they  may  be  lowered  to  the  bottom 
and  allowed  to  remain  until  cold.  If  they  can  bs 
hardened  all  right  by  dumping,  the  bath  should  be 
provided  with  an  inclined  wire  cloth  dumping  screen 
as  shown  in  Fig.  325  onto  which  the  contents  of  the 
box  should  be  dumped.  The  packing  material  will 
pass  through  the  screen  into  the  iron  pan  below 


MISCELLANEOUS   WORK. 


347 


while  the  work  will  roll  down  the  incline  into  the  oil. 
The  packing  material,  if  dumped  into  the  oil,  will 
set  it  afire,  and  also  dirty  the  oil,  rendering  it  useless. 
Some  hardeners  always  use  this  dumping  screen  even 
when  quenching  in  water. 

Examples  of  Case  Hardening. — Small  Screws.— 
As  the  stock  used  in  making  machine  screws  varies, 
it  is  necessary  to  vary  the  treatment  at  times.  If 
they  are  made  from  Bessemer  screw  wire,  bone  that 
has  been  used  once  for  short  runs  gives  better  results 


FIG.  325. 

than  raw  bone,  especially  on  small  slotted  screws.  If 
no  partially  expended  bone  is  available,  it  is  advisable 
to  char  some  as  raw  bone  will  phosphorize  the  screws 
and  make  them  extremely  brittle  and  no  amount 
of  tempering  will  remove  this  brittleness.  Screws 
larger  than  f  "  do  not  show  the  effects  of  brittleness 
as  much  as  the  smaller  sizes  as  there  is  a  large,  soft 
core  that  is  not  affected. 

Nuts. — Machine  nuts,  if  small,  and  a  deep  pene- 
tration is  not  necessary,  may  be  packed  in  small 
boxes  with  equal  parts  of  charcoal  and  raw  bone  and 


FORGE-PRACTICE. 


run  from  three  to  five  hours  according  to  size  and 
depth  of  hardness  desired.  If  the  nuts  are  to  be 
polished  after  hardening  a  little  longer  exposure  will 
be  necessary.  Nuts  f  "  and  larger  may  be  packed 
in  raw  bone  and  charcoal  of  equal  parts,  run  from 
five  to  seven  hours  and  dumped  into  the  bath.  If 
colors  are  desired,  the  flats  and  tops  of  the  nuts  must 
be  polished  and  the  packing  material  should  be  some 
mixture  especially  suited  to  the  work.  For  general 
purposes  the  following  works  well.  Eight  parts 
No.  i  charred  bone,  2  parts  animal  charcoal,  and  i 
part  charred  leather.  Excellent  results  follow  the 
use  of  the  bath  shown  in  Fig.  324  where  a  quantity 
of  air  is  introduced  into  the  bath.  If  brilliantly  col- 
ored surfaces  are  desired,  mix  a  small  amount  of  pow- 
dered cyanide  of  potassium  with  the  packing  mix- 
ture. As  previously  stated,  all  work  that  is  to  be 
colored  must  be  absolutely  clean  and  free  from  all 
grease.  In  some  hardening  plants  every  operator 
packing  work  of  this  character  wears  gloves  to  pre- 
vent the  moisture  of  the  hands  getting  on  the  work. 
It  is  advisable  to  observe  this  precaution  if  good 
results  are  desired. 

All  case  hardened  work  should  be  thoroughly 
washed  in  hot  soda  water,  then  in  boiling  water  and 
then  thoroughly  dried.  Colored  work  should  be 
oiled.  All  this  should  be  done  immediately  on 
removing  from  the  quenching  bath. 

Deep  Penetration.—  Where  very  deep  penetration 
is  desired,  it  is  necessary  to  expose  the  work  to  the 
influence  of  the  carbonizing  material  for  a  long 
period.  The  writer  has  in  mind  some  nuts  that  were 


MISCELLANEOUS   WORK. 


349 


about  1 6"  across  flats.  Instructions  called  for  a 
depth  of  carbon  penetration  of  at  least  J".  They 
also  stated  that  the  walls  of  the  holes  and  the  stock 
immediately  around  the  holes  must  be  soft  as  the 
nuts  were  to  be  threaded  after  hardening,  and  that 
the  flats  and  tops  must  be  nicely  colored.  Test 
pieces  of  steel  made  from  the  same  billet  as  the  nuts, 
came  with  them.  These  were  to  be  treated  the  same 
as  the  nuts,  and  broken  to  determine  the  depth  of 
carbon  penetration. 


FIG.  326. 

On  account  of  their  size  it  was  considered  advisa- 
ble to  pack  but  one  nut  and  its  test  piece  in  a  box. 
The  packing  material  used  was  the  coarser  grades  of 
raw  bone.  Before  packing,  a  round  plate  of  cast 
iron  \"  diameter  larger  than  the  hole,  was  pro- 
vided to  cover  each  end  of  the  hole,  as  shown  in  Fig. 
326.  These  were  provided  to  prevent  the  carbon  gas 
acting  on  the  walls  of  the  hole.  The  plates  were 
bolted  in  place  and  an  eye  bolt  provided  for  use  in 
handling.  Three  ^"  vent  holes  were  drilled  in  each 
upper  plate;  these  were  covered  with  fire  clay. 


350  FORGE-PRACTICE. 

While  carbon  will  penetrate  iron  and  steel  when  in 
contact  with  carbonaceous  materials,  it  is  a  known 
fact  that  the  material  gives  off  all  of  its  available 
carbon  in  a  few  hours ;  the  length  of  time  depending 
on  the  size  of  the  kernels.  In  the  case  of  the  nuts, 
it  was  considered  best  to  run  them  fifteen  hours,  let 
them  cool  off,  repack  in  fresh  material  and  run  for  an 
equal  length  of  time,  making  thirty  hours  that  they 
were  exposed  to  carburization,  at  a  temperature 
of  1700°  F.  They  were  packed  again  in  a  mixture 
of  charred  bone  4  parts,  charred  leather  i  part  and 
exposed  to  a  temperature  of  1450°  F.  for  four  hours 
after  they  were  red  hot. 

Dipping  the  nut  in  the  bath  was  a  comparatively 
simple  matter  as  the  plant  was  equipped  with  a 
small  crane.  The  crane  hook  was  passed  through 
the  eye  bolt  and  the  nut  dipped  in  a  large  bath  having 
six  delivery  pipes  from  the  sides,  one  from  the  bottom 
and  one  from  the  top.  The  results  were  all  that  was 
expected  as  the  penetration  was  over  \"  and  the  sur- 
faces were  nicely  colored. 

At  times,  the  ingenuity  of  the  hardener  is  taxed 
to  the  limit.  Results  that  are,  apparently,  beyond 
the  range  of  human  possibility  are  demanded  and  no 
method  for  producing  these  results  is  advanced. 
I  have  in  mind  an  instance  where  the  man  in  charge 
of  a  heat-treating  plant  was  told  that  certain  pieces 
being  case  hardened  must  show  an  increase  of  25 
per  cent  in  breaking  strength,  and,  at  the  same  time, 
show  the  same  hardness  test  as  formerly.  He  accom- 
plished the  desired  result  by  dropping  his  charging 
heat  50°  F.  and  quenching  in  water  heated  to  about 


MISCELLANEOUS   WORK.  351 

115°  F.  The  bath  was  supplied  with  water  from  an 
artesian  well.  Several  pipes  carrying  live  steam 
entered  the  supply  pipe,  each  pipe  being  provided 
with  a  valve  making  it  possible  to  get  a  range  of 
temperature  from  about  50°  F.  to  150°  F.  He  might 
have  attained  the  desired  strength  by  quenching  in 
oil,  but  as  the  pieces  had  but  a  short  time  exposure 
to  the  carburizer  they  would  not  show  the  necessary 
hardness  when  tested. 

Local  Case  Hardening. — This  term  is  applied  to 
the  practice  of  hardening  one  or  more  portions  of  a 
piece  leaving  the  balance  soft,  and  is  accomplished 
by  a  number  of  methods.  One  method  consists  in 
charging  carbon  into  a  piece  of  work  then  cutting 
away  the  carbonized  surface  where  hardness  is  not 
desired.  Another  method  is  to  protect,  by  some 
means,  the  portions  desired  soft,  so  that  the  carbon 
will  not  penetrate.  A  third  method  consists  in 
charging  carbon  into  all  surfaces,  then  protecting 
the  portion  desired  soft  by  means  of  holders,  or 
special  tongs.  As  an  example  of  the  first  method  we 
will  consider  the  block  shown  in  Fig.  327  where  the 
projecting  ring  (a)  is  the  only  portion  desired  hard. 
The  block  was  rough  machined,  the  ring  was  ma- 
chined to  within  grinding  size  on  top  and  to  within 
^j"  of  finish  dimension  for  thickness  and  -£3"  depth. 

When  packed  for  carburizing  a  thoroughly  ex- 
pended bone  was  placed  in  the  box  to  a  depth  of  2" 
and  on  this  the  block  was  placed  with  the  ring  upper- 
most. The  hole  was  filled  with  expended  bone,  and 
the  same  material  was  placed  around  the  block  to 
within  \"  of  the  top.  Raw  bone  of  medium  size 


352 


FORGE-PRACTICE. 


granules,  mixed  with  an  equal  amount  of  wood 
charcoal,  was  then  put  in,  covering  the  ring  to  a 
depth  of  i".  The  balance  of  space  was  filled  with 
expended  bone.  The  block  was  then  subjected  to  a 
temperature  of  I/500  F.  for  eight  hours  after  it  was 
red  hot.  The  box  was  then  removed  from  the  fur- 


FIG.  327. 

nace  and  allowed  to  cool.  After  cooling  the  block 
was  machined  to  finish  dimensions,  then  reheated 
to  1480°  F.  in  a  box  with  no  packing  material,  except 
that  the  ring  was  covered  on  top  and  sides  with  dry 
fire  clay,  to  a  thickness  of  J"  to  prevent  oxidation  of 
the  surfaces. 


MISCELLANEOUS  WORK. 


353 


When  the  piece  was  uniformly  heated  to  the  tem- 
perature mentioned  (1480°  F.)  it  was  placed  on  a 
specially  prepared  holder  and  a  large  stream  of 
water  projected  against  either  end,  as  shown  in  Fig. 
283.  The  purpose  of  the  stream  against  the  bottom 
of  the  block  was  to  cause,  so  far  as  possible  uniform 
contraction  of  the  piece.  It  had  been  found,  by 
experience,  that  satisfactory  results  were  not  ob- 
tained by  immersing  in  a  tank  as  the  vapors  formed 
did  not  allow  the  water  free  access  to  the  ring. 
In  the  open  air  with  a  large,  strong  jet  of  water  these 
vapors  were  easily  taken  care  of. 

By  the  second  method  mentioned,  the  portions 
desired  soft  are  protected  from  the  action  of  the 
carbon  gas  by  covering  with  sheet  iron  or  steel. 
These  covers  may  be  wired  in  position.  Or  the 
portions  may  be  covered  with  wet  fire  clay,  wound 
with  wire  to  prevent  its 
cracking  away  or  a  mixture 
of  fire  clay  and  asbestos 
may  be  used.  Where  local 
case  hardening  is  done  in 
large  batches  special  cast- 
iron  covers  are  made  to 
protect  certain  portions 
desired  soft.  Or  the  por- 
tions may  be  plated  with 
either  nickel  or  copper,  this 
is  costly  and  seldom  re- 
sorted to  where  any  of  the  other  methods  will  answer. 

As  an  example  of  the  third  method  we  will  con- 
sider the  piece  shown  in  Fig.  328  where  a  pair  of  tongs 


1 


FIG.  328. 


354  FORGE-PRACTICE. 

is  used  to  protect  the  portion  desired  soft  from  the 
action  of  the  bath.  Under  certain  conditions  it 
may  be  advisable  to  cool  the  ends  in  water  until  the 
red  has  disappeared,  then  to  remove  them  from  the 
water  bath  and  drop  the  piece  from  the  tongs  into  a 
bath  of  oil.  This  will  stiffen  and  toughen  the  center 
portion  without  actually  hardening  it.  Special 
holders  are  many  times  used  instead  of  tongs. 

Fine  Grain. — The  process  of  case  hardening,  as 
ordinarily  practiced,  tends  to  produce  a  coarse  grain 
in  the  carbonized  portion.  For  many  purposes  this 
does,  not  injure  the  product.  As  the  size  of  the  grain 
is  directly  proportional  to  the  temperature  given  the 
steel,  extremely  coarse  texture  may  be  avoided  by 
employing  low  heats  in  charging.  In  many  cases 
this  is  objectionable  on  account  of  the  time  necessary 
to  secure  a  desired  penetration,  as  carbon  pene- 
trates faster  at  high  heats.  To  secure  rapid  pene- 
tration and  yet  get  a  compact  grain  two  heats  are 
many  times  employed.  This  is  a  modification  of  the 
Harveyizing  process,  and  consists  in  packing  the 
pieces  for  carburizing  in  the  usual  manner  and 
running  at  a  temperature  of  1750°  F.  to  1850°  F. 
for  a  length  of  time  necessary  to  give  desired  pene- 
tration, then  allow  the  pieces  to  cool,  and  reheat 
and  harden  as  though  they  were  of  tool  steel,  except 
that  slightly  higher  temperatures  are  employed 
(about  1475°  F.)  than  for  high-carbon  tool  steels. 

Under  some  conditions  two  quenchings  are  made, 
the  first  at  a  high  temperature  1650°  to  1750°  F., 
and  then  a  second  at  1400°  to  1450°  F.  Unless  this 
method  is  necessary  to  produce  desired  results  its  use 


MISCELLANEOUS  WORK.  355 

is  not  to  be  advocated  on  account  of  the  expense 
involved.  The  writer  does  not  wish  to  be  under- 
stood as  advocating  the  exact  temperatures  men- 
tioned, as  they  must  be  adapted  to  the  materials 
used,  the  design  of  the  piece,  and  the  use  to  which  it 
is  to  be  put. 

As  modern  -manufacturing  conditions  demand  a 
higher  grade  of  case-hardened  product  than  was 
formerly  the  case,  dumping  into  the  bath  directly 
from  the  charging  heat  is  not  practiced  to  as  great 
an  extent  as  it  was  at  one  time.  In  some  shops  a 
very  large  proportion  of  case-hardened  work  is 
given  two  heats,  i.e.,  the  first  for  charging  and  the 
second  for  hardening.  This  practice  is  especially 
desirable  where  a  pronounced  line  of  demarkation, 
at  the  point  where  the  hardened  portion  joins  the 
soft  core,  is  objectionable. 

The  depth  of  penetration  of  carbon  should  be  no 
greater  than  is  necessary  to  produce  desired  results. 
It  is  folly  to  run  work,  in  the  process  of  carburizing, 
for  eight  hours,  when  an  exposure  of  five  hours  will 
give  a  penetration  sufficiently  deep. 

Under  some  conditions  it  is  necessary  to  draw  the 
temper  after  case  hardening,  this  practice  is  resorted 
to  where  it  is  necessary  to  use  a  comparatively  high- 
carbon  steel  in  order  to  get  a  strong  core. 

Case  Hardening  Brazed  Articles. — At  times  it  is 
desirable  to  case  harden  articles  that  have  been 
brazed.  Where  possible  such  pieces  should  be 
brazed  with  a  fairly  high-temperature  spelter,  but 
the  hardener  seldom  has  anything  to  say  about 
what  shall  be  done  to  articles  before  they  reach  his 


FORGE-PRACTICE. 


department.  For  this  reason  it  is  advisable  to  heat 
one  of  the  pieces  in  an  open  fire  and  see  if  the  brazing 
starts  at  a  full  red  heat,  if  it  does  not  it  is  safe  to 
pack  the  pieces  in  a  box  with  a  desirable  carburizer 
and  run  at  a  low  red  heat,  making  sure  that  this  tem- 
perature is  not  exceeded  at  any  time,  and  proceed 
as  in  any  ordinary  case  hardening.  When  quench- 
ing work  of  this  kind  it  is  not  advisable,  generally 
speaking,  to  dump.  The  pieces  should  be  quenched 
singly  in  such  a  manner  as  not  to  bring  any  strain 
on  the  brazed  joint. 

The  writer  has  case  hardened  many  thousand 
pieces  of  brazed  work.  In  some  cases  the  object 
sought  was  a  hard  surface  ;  in  others  it  was  to  stiffen 
the  stock  so  it  would  stand  a  high  torsional,  or  other 
strain. 

Carburizing  with  Gas.  —  There  have  been  many 
changes  and  advances  made  during  the  past  twenty- 
five  years  in  the  process  of  case  hardening,  none  of 
which  are  of  more  importance  to  the  manufacturer 
who  finds  it  necessary  to  produce  a  deep  penetration 
of  carbon  than  the  method  of  carbonizing  with  gas. 

Armor-plate  manufacturers  were  handicapped 
when  treating  the  plates  by  means  of  solid  carbon- 
izers,  and  experimented  with,  and  perfected,  a  process 
whereby  the  carbonizing  could  be  accomplished  by 
means  of  carbonaceous  gas.  The  success  of  this 
method  has  led  manufacturers  of  heating  furnaces 
to  place  on  the  market  muffle  furnaces  using  gas  as  a 
carburizer.  By  this  method  more  uniform  results 
are  obtained,  especially  where  deep  penetration  is 
desired,  than  by  the  use  of  solid  carbons.  As  the 


MISCELLANEOUS  WORK. 


357 


gas  can  be  constantly  fed  to  the  heated  pieces  any 
desired  depth  of  penetrations  can  be  obtained  without 
the  bother  and  expense  of  repacking.  A  gas  car- 
bonizing machine  is  shown  in  Fig.  329. 


FIG.  329. 

Baths  of  Cyanide  of  Potassium. — Gun  frames, 
parts  of  apparatus  and  seme  forms  of  tools  where 
highly  colored  surfaces  are  desired,  are  case  hardened 
by  heating  in  a  crucible  of  red-hot  cyanide  of  potas- 
sium and  then  dipping  in  cold  water.  As  in  all 
methods  of  producing  color  work  the  surfaces  must 
be  nicely  polished  and  absolutely  clean  before  case 
hardening. 


FORGE-PRACTICE. 


The  work  must  be  suspended  in  the  crucible  in 
such  manner  that  it  is  entirely  submerged  in  the 
cyanide  and  so  it  does  not  touch  the  crucible  at  any 
point.  This  is  usually  accomplished  by  means  of 
hooks  suspended  from  rods  placed  across  the  top  of 
crucible. 

For  most  small  work  a  Cyanide  Hardening  Fur- 
nace of  the  type  shown  in  Fig.  330  answers  very  well. 
Where  the  pieces  are  of  a  size  and  form  that  does  not 
make  possible  the  use  of  one  of  the  commercial  types, 
a  furnace  and  crucible  designed  to  meet  the  require- 
ments can  be  built.  Cast-iron  crucibles  work  nicely 
in  heating  cyanide  as  the  temperatures  employed  are 
never  extremely  high  when  producing  colors.  The 
exact  temperature  depends  on  the  character  of  the 
work,  generally  from  1375°  to  1450°  F. 

The  pieces  should  be  left  in  the  cyanide  until 
uniformly  heated,  and  as  much  longer  as  is  necessary 
to  produce  the  desired  depth  of  penetration.  If 
colored  surfaces  with  slight  penetration  is  desired 
the  pieces  should  be  removed  and  quenched  when 
uniformly  heated  to  the  proper  temperature. 

Any  form  of  moisture  must  not  be  allowed  to  enter 
the  crucible  as  the  resulting  steam  would  cause  par- 
ticles of  the  melted  cyanide  to  fly,  these  produce 
painful  burns  which,  on  account  of  the  poisonous 
nature  of  the  chemical,  are  slow  in  healing.  For 
this  reason  the  operator  should  always  wear  goggles 
to  protect  the  eyes  and  long  gloves  to  cover  the  hands 
and  arms. 

Hooks  and  tongs  should  be  dried  after  use  in 
quenching  before  using  again.  For  this  reason  a 


MISCELLANEOUS  WORK. 


359 


plentiful  supply  of  hooks,  and  several  pairs  of  tongs 
must  be  provided.  Furnaces  are  sometimes  de- 
signed with  a  drying  chamber  so  located  that  the 


FIG.  330. 

operator  can  place  the  hooks  and  tongs  in  it,  and 
remove  them  without  loss  of  time. 

Articles   made   from   tool  steel,   and  other  high- 
carbon    steels,    are    many  times  hardened  by   this 


FORGE-PRACTICE. 


method  in  order  to  get  the  brilliantly  colored  sur- 
faces. In  case  the  resulting  hardness  is  too  great 
the  temper  may  be  drawn  the  desired  amount  by 
means  of  an  oil- tempering  furnace  without  injuring 
the  colors ;  provided  the  pieces  are  allowed  to  remain 
in  the  oil  until  cooled  below  400°  F. 

As  a  rule  extremely  cold  quenching  baths  produce 
more  brilliantly  colored  surfaces  than  those  whose 

temperature  is  above 
50°  F.  For  this  reason 
it  is  customary  in  some 
hardening  plants  to 
keep  ice  in  the  tank 
in  warm  weather  un- 
less the  water  is  from 
an  artesian  well  or 
some  supply  that  in- 
sures the  desired  temp- 
erature. 

If  the  fine  vine-like 
bluish  lines  sometimes 
observed  on  high-grade 
case-hardened  work  are 
desired  they  may  be 
produced  by  using  a 

bath  of  the  design  shown  in  Fig.  331.  The  ends 
of  supply  pipes  which  are  located  above  the  tank  are 
so  constructed  that  the  water  comes  from  them  in 
the  form  of  spray.  The  heated  pieces  are  passed 
through  this  spray  then  into  the  bath  where  they 
are  worked  around  in  the  water  until  cool. 

Many    forms    of    dies,    especially    those    having 


FIG.  331. 


MISCELLANEOUS   WORK.  361 

engraving  on  the  working  faces,  molds  used  in  form- 
ing various  substances  to  shape  and  numerous  other 
articles  are  heated  in  red-hot  cyanide  for  hardening; 
but  in  such  cases  colors  are  not  sought.  Molten 
cyanide  provides  an  excellent  means  of  heating  pieces 
that  must  be  free  from  oxidation,  and  which  would 
not  prove  satisfactory  if  heated  in  lead. 

Melted  cyanide  gives  off  poisonous  fumes  which 
are  harmful  if  inhaled.  Furnaces  used  for  the  pur- 
pose under  consideration  should  be  provided  with 
some  means  of  getting  rid  of  these  fumes,  the  one 
shown  in  Fig.  330  has  a  pipe  connected  with  the 
chimney. 

HIGH    SPEED    STEEL 

Forging  High-Speed  Steel. — For  tools  to  be  used 
in  taking  medium  and  light  cuts,  tool  bits  for  use  in 
tool  holders  are  advocated  as  they  answer  every 
purpose  and  are  much  cheaper  than  forged  tools. 
The  desired  shape  can  be  produced  by  grinding,  one 
holder  answering  for  the  various  forms  of  tools  used 
on  a  machine.  This  applies,  of  course,  to  tools  used 
on  lathes,  planers,  etc.,  particularly  the  former. 

In  the  case  of  milling  cutters,  blanks  can  be  pro- 
cured of  a  size  that  allows  for  the  necessary  machin- 
ing. Punches  are  best  made  from  bar  stock  even 
where  considerable  turning  or  other  machining  is 
necessary  as  such  pieces,  especially  if  round  in  form, 
are  liable  to  burst  from  forging  strains  of  a  nature 
that  cannot  be  removed  by  annealing. 

At  the  present  time  there  is  comparatively  little 


362  FORGE-PRACTICE. 

trouble  experienced  when  forging  the  ordinary  forms 
of  lathe  tools.  Smiths  have  become  familiar  with 
the  higher  temperature  necessary  for  high-speed 
steel  than  is  employed  for  carbon  and  the  ordinary 
alloy  steels.  To  get  satisfactory  results  it  is  abso- 
lutely necessary  that  the  steel  be  uniformly  heated 
throughout.  If  the  interior  is  hotter  than  the  outer 
portion,  cracks  will  develop  near  the  center  from 
uneven  contraction  when  cooling.  These  defects 
are  not  easily  detected  as  the  exterior  may  be  per- 
fectly sound.  If  the  exterior  is  much  hotter  than 
the  interior  surface  checks  will  result.  High-speed 
steel  should  not  be  hammered  when  it  is  below  a 
full  red  heat,  the  temperature  range  recommended 
by  several  manufacturers  is  1650°  to  1850°  F., 
although  in  no  case  should  it  be  hammered  when  it 
gives  a  metallic  ring.  The  objection  to  high  heats 
is  that  tools  so  treated  do  not  stand  up  as  well. 
Most  steel  makers  furnish  general  directions  for 
forging  and  hardening  which  are  many  times  given 
in  colors  and  it  is  rather  difficult  to  determine  just 
what  is  meant,  because  one  authority's  understanding 
of  the  temperature  corresponding  to  a  certain  color 
is  liable  to  differ  materially  from  that  expressed  by 
another.  For  this  reason,  the  smith  when  possible 
should  ascertain  by  experiment  the  temperature 
that  gives  the  best  results  with  the  steel  he  is  using 
and  the  tools  he  is  forging.  A  heat  that  may  insure 
ease  in  forging  may  not  put  the  tool  in  the  best  con- 
dition possible  for  producing  the  greatest  amount  of 
work  in  a  given  time.  The  smith  should  always 
bear  in  mind  the  fact  that  his  office  is  not  to  produce 


MISCELLANEOUS  WORK.  363 

the  greatest  number  of  tools  in  a  given  time,  but 
rather  to  produce  tools  that  will  turn  out  the  max- 
imum amount  of  woik  in  a  given  time.  Unfor- 
tunately, it  is  the  custom  in  some  establishments  to 
judge  a  smith's  ability  by  the  number  of  passable 
tools  he  turns  out  rather  than  by  the  amount  of  work 
these  tools  produce  in  a  given  time. 

Form  of  Tools. — The  form  of  a  tool  must  depend 
on  the  character  of  the  work  and  the  condition  of  the 
metal  it  is  to  be  used  on.  If  a  tool  is  to  be  used  on 
work  requiring  coarse  feeds  it  must  be  given  an  angle 
of  inclination  with  the  cut  that  will  insure  sufficient 
clearance  below  the  cutting  edge  so  that  the  work 
will  not  rub  on  the  tool  below  the  cutting  edge ;  this 
amount  of  clearance  would  not  be  absolutely  neces- 
sary if  fine  feeds  were  to  be  employed.  If  the  exact 
amount  of  feed  is  not  known  it  is  best  to  give  suffi- 
cient inclination  so  that  the  tool  will  answer  in  any 
case. 

The  writer's  attention  was  at  one  time  called  to 
several  tools  that  "fell  down"  in  a  competitive  test. 
The  concern  handling  the  steel  was  not  satisfied  with 
the  results  of  the  test  and  ordered  an  investigation. 
An  examination  of  the  tools  showed  that  there  was 
very  little  angle  on  the  side  of  the  tool  as  shown  in 
Fig.  332,  and  as  coarse  feeds  were  employed  in  the 
tests  it  was  impossible  for  the  tools  to  cut.  They 
were  heated  and  bent  to  a  greater  angle  as  shown  in 
Fig.  333.  In  the  second  test  they  stood  No.  i  instead 
of  being  at  the  bottom  of  the  list.  An  intelligent 
study  of  tool  angles  is  just  as  essential  for  the  smith 
as  a  study  of  temperatures. 


364 


FORGE-PRACTICE. 


As  a  rule  tools  to  be  held  in  tool  posts  should  be 
made  from  annealed  stock  and  as  this  can  be  pur- 
chased at  prices  less  than  that  of  unannealed  stock 
plus  the  cost  of  annealing  in  the  average  shop  it  is 
not  wise  to  attempt  the  annealing  of  bars  in  shops 
having  the  ordinary  furnace  equipment.  If  the 
stock  is  bought  in  the  unannealed  condition  it  must 
be  heated  to  cut  to  length. 


FIG.  332. 


FIG.  333. 


Annealing. — High-speed  steel  can  be  annealed  so 
it  is  nearly  as  soft  as  carbon-tool  steel.  To  accom- 
plish this,  however,  the  proper  facilities  must  be  at 
hand  and  the  steel  must  be  slowly  heated  to  the 
proper  temperature  and  allowed  to  remain  at  this 
temperature  for  a  time  that  insures  an  absolutely 
uniform  heat,  then  cooled  very  slowly.  Long  con- 
tinued soaking  should  be  avoided  as  it  is  apt  to  pro- 
duce a  coarse  grain  and  set  up  strains  that  are  liable 
to  cause  the  steel  to  crack  when  hardened.  The  steel 
may  be  annealed  in  the  bars  by  packing  in  iron  pipes 
having  one  end  tightly  closed  by  means  of  a  cap  or 
plug.  The  pipe  should  be  somewhat  longer  than  the 


MISCELLANEOUS   WORK.  365 

bars  in  order  that  the  open  end  may  be  closed  with  a 
loosely  fitting  plug  and  securely  sealed  with  fire  clay. 
Several  small  holes  should  be  drilled  through  this 
plug  to  allow  gas  to  escape  or  the  clay  lutting  will 
be  blown  away.  The  bars  when  in  the  pipe  should 
be  surrounded  with  green  coal  dust,  powdered  char- 
coal, powdered  coke  or  some  substance  that  will 
give  off  a  gas  that  prevents  oxidation  of  the  surface. 
The  pipes  when  packed  may  be  placed  in  the  fur- 
nace and  gradually  brought  up  to  low  red  (1400°  to 
1450°  F.).  The  steel  should  be  uniformly  heated 
and  should  not  be  soaked  in  the  fire,  as  long-continued 
heats  produce  a  coarse  structure  and  tend  to  increase 
the  liability  to  rupture  when  the  steel  is  hardened. 

When  the  bars  are  uniformly  heated  to  the  tem- 
perature mentioned  the  heat  may  be  shut  off  and  the 
whole  allowed  to  cool.  Any  openings  in  the  furnace 
should  be  closed  as  cold  air,  if  it  enters  the  furnace, 
chills  the  steel  and  retards  the  annealing  operation. 

Box  Annealing. — When  annealing  forgings,  tool 
blanks,  etc.,  it  is  advisable  to  pack  in  boxes  of  con- 
venient size  using  as  packing  materials  powdered 
charcoal,  coal,  coke,  or  something  that  gives  off  a 
non-oxidizing  gas.  However,  some  parties  claim 
good  results  from  the  use  of  asbestos,  ashes,  lime  or 
sand.  The  writer  has  had  good  results  from  the  use 
of  finely  powdered  dry  fire  clay.  A  space  of  ij" 
should  be  left  between  the  top  of  the  packed  work 
and  the  cover  which  should  be  filled  with  the  packing 
material.  The  cover,  which  has  three  or  four  small 
holes  drilled  at  the  center  to  allow  gas  to  escape, 
should  be  placed  in  position  and  sealed. 


366 


FORGE-PRACTICE. 


When  a  box  of  the  description  shown  in  Fig.  334  is 
used  sealing  with  wet  fire  clay  is  not  necessary.  The 
groove  is  quite  a  little  wider  than  the  cover  flange, 
this  allows  a  packing  of  finely  sifted  ashes,  or  dry 
powdered  fire  clay  between  the  flange  and  walls  of 
groove  thus  preventing  air  entering  the  box.  The 
interior  of  the  box  may  be  lined  with  fire  brick  if  this 
seems  advisable.  As  a  rule,  however,  a  cast-iron 


FIG.  334. 


Dumping  Fork  for  Fig.  334. 

box  with  reasonably  thick  walls  and  no  lining  will 
be  found  satisfactory. 

If  possible  the  boxes  should  be  placed  in  the  fur- 
nace at  such  a  time  that  the  completion  of  the  run 
will  come  at  about  the  time  of  shutting  off  the  fur- 
naces at  night,  so  that  the  boxes  can  be  left  in  until 
morning.  This  arrangement,  however,  is  not  always 
possible,  and  they  must  be  removed  from  the  fur- 


MISCELLANEOUS   WORK.  367 

nace  when  heated  long  enough  and  buried  in  very 
hot  sand  or  ashes. 

Pieces  2"Xi"X6"  should  be  held  at  the  annealing 
temperature  for  about  three  hours.  If  very  much 
larger  than  2//Xi//  the  time  should  be  increased 
somewhat,  always  avoiding  long  heats  from  the  time 
the  pieces  are  uniformly  heated  to  the  proper  tem- 
perature. Always  avoid  overheating.  If  the  tem- 
perature is  raised  much  above  1500°  F.  hardness 
results,  as  it  is  approaching  the  temperature  where 
the  changes  take  place  in  the  steel  that  produces 
hardness  even  if  slow  cooling  is  resorted  to.  Never- 
theless, if  the  heats  do  exceed  1500°  F.  slower  cooling 
must  be  resorted  to. 

To  Anneal  Without  Discoloring. — If  it  is  necessary, 
or  desirable  to  anneal  articles  having  polished  sur- 
faces without  oxidizing  or  discoloring  them,  it  may 
be  done  by  taking  a  piece  of  gas  pipe  of  convenient 
size  and  length  and  thread  both  ends.  On  one  end 
permanently  screw  a  cap  having  one  or  two  TJT" 
holes  drilled  through  it.  The  cap  to  go  on  the  other 
end  should  be  drilled  and  threaded  to  receive  a  £" 
gas  pipe.  The  articles  to  be  annealed  should  be 
placed  in  the  pipe,  the  cap  screwed  on  and  the  whole 
placed  in  the  furnace  with  the  end  that  is  to  receive 
the  i"  pipe  towards  the  front.  The  small  pipe 
should  be  screwed  to  place  and  connected  with  an 
illuminating  gas  supply,  as  shown  in  Fig.  335.  When 
the  gas  is  turned  on  it  should  be  immediately  lighted 
at  the  opposite  end  of  the  pipe  as  it  escapes  from  the 
small  holes. 

The  furnace  heat  should  be  turned  on  and  the 


368 


FORGE-PRACTICE. 


operation  carried  on  as  in  ordinary  annealing  of 
high-speed  steel.  When  the  pieces  have  been  heated 
for  the  proper  length  of  time  the  furnace  heat  may  be 
shut  off  but  the  gas  should  be  allowed  to  pass  through 
the  tube  and  burn  until  the  pieces  are  cooled  to  below 
400°  F. 

The  gas  passing  through  the  pipe  mixes  with  the 
air  in  the  pipe  and  carries  it  out  before  an  oxidizing 
temperature  is  reached,  after  which  the  flow  of  gas 
excludes  all  air,  and  as  oxidation  cannot  take  place 
unless  air  is  present  the  surfaces  will  be  clear  and  free 
from  oxide. 


Gas  Pipe 


FIG.  335. 


A  modification  of  the  process  just  described  con- 
sists in  placing  a  small  quantity  of  resin  in  the  bot- 
tom of  the  hardening  box,  packing  the  work  in  the 
box  surrounding  each  piece  with  powdered  charcoal 
and  then  placing  another  small  amount  of  resin  on 
top.  The  cover  should  have  a  few  small  holes 
drilled  through  it  to  allow  the  gas  to  escape  and 
should  be  securely  sealed  and  the  process  carried  on 
as  in  ordinary  annealing.  This  method  is  also  em- 
ployed in  annealing  articles  made  from  carbon  steel 
and  when  discoloration  of  surfaces  is  undesirable. 

Quick  Annealing.— While  fairly  good  results  are 
sometimes  obtained  by  rapid  annealing,  the  prac- 


MISCELLANEOUS  WORK.  369 

tice  is  one  the  writer  does  not  advocate,  but  like  a 
number  of  other  practices  which  cannot  be  encour- 
aged there  are  times  when  it  must  be  resorted  to.  A 
tool  may  be  heated  very  slowly  to  a  low  red  and  buried 
in  lime,  ashes,  asbestos,  or  sand  that  has  been  heated 
very  hot  and  allowed  to  cool  very  slowly.  A  method 
employed  by  an  acquaintance  consists  in  heating  as 
described  above  and  plunging  in  water  at  a  tem- 
perature of  200°  F. 

Lathe,  planer,  and  similar  tools  should  be  an- 
nealed after  forging  and  before  hardening.  As  the 
object  of  this  annealing  is  to  overcome  forging  strains 
which  otherwise  would  manifest  themselves  when 
the  piece  is  hardened,  it  may  be  accomplished  by 
allowing  them'  to  cool  down  to  a  black  after  forging 
then  re-heating  to  a  low  red  and  placing  in  a  warm 
dry  place  and  leaving  until  cold. 

Hardening  High-Speed  Steel. — There  are  many 
makes  of  high-speed  steels  on  the  market,  some  of 
which  require  special  treatment  in  hardening.  The 
majority,  however,  respond  to  the  same  treatment 
and  it  is  with  this  class  we  shall  deal  when  consider- 
ing the  treatment  necessary  to  obtain  good  results. 
The  furnace  used  has  a  great  deal  to  do  in  obtaining 
the  right  temperature.  In  some  instances  those 
designed  for  use  in  heating  carbon  steels  can  be  used 
with  good  results  in  treating  high-speed  steel,  but  as 
a  rule  specially  designed  furnaces  should  be  used. 

Coke  furnaces  properly  made  and  tended  are  used 
with  good  results  in  some  shops,  but  generally  those 
burning  gas  or  oil  give  best  results  and  do  not  have 
the  interruption  necessary  when  cleaning  and  replen- 


370  FORGE- PRACTICE. 

ishing  coke  fires.  As  extremely  high  heats  are  neces- 
sary two  or  more  furnaces  should  be  used.  The 
pieces  should  be  pre-heated  before  placing  in  the 
high  temperature  furnace,  or  the  steel  will  be  weak- 
ened or  ruptured.  The  pre-heating  should  be  com- 
paratively slow,  and  to  a  temperature  of  about 
1500°  F.,  when  the  pieces  should  be  transferred  to 
the  high  temperature  furnace  and  rapidly  heated 
the  desired  amount.  This  temperature  necessarily 
varies  according  to  the  character  of  the  tool.  Taps, 
milling  cutters,  and  other  tools  having  slender  pro- 
jecting teeth  cannot  be  heated  to  as  high  a  tempera- 
ture as  ordinary  lathe,  planer,  and  similar  tools. 
For  the  former,  if  made  from  most  of  the  standard 
American  high-speed  steels,  a  temperature  of  2250° 
to  2450°  F.  is  recommended.  While  most  lathe, 
planer  and  similar  tools  to  be  used  for  rough,  heavy 
work,  and  whose  design  allows  of  grinding  after 
hardening,  should  be  heated  nearly  to  the  melting 
point;  in  fact  in  many  cases  it  is  advisable  to  heat 
until  the  edges  and  corners  "drip,"  melting  does 
not  occur,  in  most  high-speed  steels,  below  a  tem- 
perature of  2550°  F.  Where  grinding  is  not  allow- 
able after  hardening  slightly  lower  heats  must  be 
observed. 

Fig.  336  shows  a  furnace  provided  with  a  preheat- 
ing chamber  immediately  above  the  high-tempera- 
ture chamber.  The  waste  gases  from  the  lower 
chamber  heat  the  upper  one,  effecting  a  considerable 
saving  in  fuel.  After  the  furnace  has  been  in  opera- 
tion for  some  time  the  upper  chamber  may  become 
too  hot  for  pre-heating  extremely  complicated  tools 


MISCELLANEOUS   WORK. 


371 


in  which  case  the  tools  may  be  placed  on  top  of  the 
furnace  and  transferred  to  the  pre-heating  chamber 
afterward. 

Fig.  337  shows  a  furnace  having  three  chambers, 
the  upper  one  being  used  in  drawing  the  temper  of 
tools  or  for  cold  steel  until  heated  somewhat,  and 


FIG.  336. 

before    placing    in     the     second,    or     pre-heating 
chamber. 

Electric  Furnaces. — Excellent  results  are  claimed 
by  some  from  the  use  of  electrically  heated  furnaces, 
especially  in  the  treatment  of  certain  classes  of  small 
tools.  The  cost  of  operating  this  type  is  apt  to  be 
rather  high. 


372 


FORGE-PRACTICE. 


Lead  Pot. — Lead  heated  white  hot  in  a  crucible 
was  formally  used  very  extensively  in  heating  high- 
speed steel.  Its  use  has  given  way  to  the  barium 


F 


FIG.  337. 

chloride  process  of  heating  in  a  few  plants,  and  to 
the  especially  designed  high-speed  steel  furnaces 
in  most  shops.  However,  it  is  employed  in  a  few 
places  in  getting  the  final  heats  on  milling  cutters 


MISCELLANEOUS  WORK,  373 

and  similar  tools.  The  tendency  of  the  lead  to 
rapidly  oxidize  at  high  temperatures  may  be  over- 
come to  a  degree  by  keeping  the  surface  covered 
with  finely  broken  wood  charcoal.  A  very  serious 
objection  to  the  use  of  the  lead  bath  is  the  poisonous 
gases  given  off  by  it.  As  these  gases  are  heavier 
than  air  it  is  difficult  to  conduct  them  away  by  any 
ventilating  system  that  will  not  cool  the  lead. 

Salt  Baths. — Various  salts  are  used  as  heating 
baths  for  high-speed  steel.  These  salts  are  held  in 
crucibles  in  some  form  of  specially  designed  furnace 
using  coal,  gas,  coke  or  oil  as  fuel.  Generally  speak- 
ing, gas  and  oil  give  best  results  as  a  more  uniform 
heat  can  be  obtained.  Specially  designed  electrically 
heated  furnaces  are  used  in  connection  with  salt 
baths  and  excellent  results  are  claimed  by  the  makers, 
and  by  some  users.  Before  deciding  to  install  any 
electrically  heated  furnace  the  reader  is  advised  to 
get  in  touch  with  parties  who  have  had  them  in 
constant  use  on  a  commercial  basis  for  some  time  and 
get  their  opinions  as  to  their  relative  value  and  cost 
of  maintenance.  When  making  such  inquiries  it  is 
well  to  bear  in  mind  the  fact  that  an  electric  fur- 
nace can  be  operated  much  more  economically  by  a 
firm  generating  electricity  on  a  large  scale,  or  by  one 
having  a  constant  water  power  used  for  generating 
purposes. 

It  is  undoubtedly  true  that  electrically  heated 
furnaces  can  have  their  temperatures  more  accu- 
rately controlled  than  those  heated  by  other  means, 
especially  when  heating  small  articles.  Some  users, 
however,  claim  that  the  temperatures  of  such  fur- 


374  FORGE-PRACTICE. 

naces  fluctuate  more  when  large  pieces  are  immersed 
than  is  the  case  when  gas  or  oil  is  used  as  fuel.  It  is 
also  claimed  by  some  that  under  certain  conditions 
steel  heated  in  electrically  heated  baths  shows  a 
decided  tendency  to  pitted  surfaces. 

When  it  is  necessary  to  use  two  separate  furnaces  in 
heating  they  should,  if  possible,  be  located  near  each 
other  to  avoid  cooling  of  light  sections  and  the  oxi- 
dation resulting  from  exposing  the  steel  to  the  air 
when  transferring  from  one  to  the  other. 

As  a  rule  it  is  advisable  to  anneal  articles  made 
from  high-speed  steel  before  they  are  heated  for 
hardening.  This  is  especially  true  of  lathe,  planer, 
and  similar  tools.  Annealing  relieves  forging  and 
other  strains  which  are  liable  to  manifest  themselves 
when  the  piece  is  hardened.  It  is  always  best  to 
anneal  reworked  tools  before  hardening.  In  one 
factory  it  was  found  that  tools  used  in  removing 
stock  from  the  inside  of  projectiles  when  worn  below 
size  could  be  heated  to  a  forging  temperature  flatted 
and  ground  to  size  and  re-hardened,  but  their  life 
was  only  about  40  per  cent  of  that  shown  by  new 
tools.  Investigation  showed  that  after  being  flatted 
they  were  ground  and  hardened  without  annealing. 
Orders  were  given  to  anneal  after  forging,  as  a  result 
the  tools  were  found  to  be  95  per  cent  efficient. 

At  the  present  time  the  customary  method  of 
cooling  high-speed  steel  when  hardening  is  to  dip  in 
an  oil  bath  rather  than  to  cool  in  a  blast  of  air. 
Cotton-seed  oil,  or  fish  oil  works  well  as  a  quenching 
medium  for  some  classes  of  tools,  while  others  show 
better  results  if  dipped  in  one  of  the  lighter  oils. 


MISCELLANEOUS  WORK.  375 

Kerosene  used  alone,  or  added  to  some  of  the  heavier 
oils  is  used  in  some  hardening  plants  with  excellent 
results.  Extreme  care  should  be  exercised  if  kero- 
sene is  used.  The  heated  steel  should  be  -passed 
down  through  the  surface  so  that  all  portions  of 
the  heated  steel  are  completely  covered  to  prevent 
the  oil  catching  fire.  If  this  bath  is  used  precautions 
that  will  prevent  burns  and  fires  should  be  observed. 

Pack  Hardening  High-Speed  Steel.— While  lathe, 
planer  and  similar  tools  show  best  results  when  heated 
to  the  highest  temperature  possible  without  melting, 
and,  in  fact,  when  it  can  be  done  the  temperature 
should  be  high  enough  to  cause  the  edges  to  drip. 
Such  heats  are  not  possible  when  treating  taps, 
formed  milling  cutters,  punch-press  dies,  forming 
tools  and  similar  articles.  Experience  shows  that 
such  tools  give  excellent  results  when  pack  hardened. 
When  employing  this  method  the  tools  should  be 
packed  in  charred  leather  and  run  at  a  temperature 
ranging  from  1750°  to  2200°  F.  according  to  the 
character  of  the  tool  and  the  use  to  which  it  is  to  be 
put. 

Milling  cutters  and  similar  tools  whose  design 
allows  of  grinding  after  hardening  and  which  are  to  be 
used  for  heavy  roughing  cuts  may  be  heated  higher 
than  the  temperatures  mentioned  above,  the  heats 
ranging  from  2250°  to  2350°  F.,  while  those  to  be 
used  for  light  and  finishing  cuts  may  not  require 
more  than  2100°  F.  Threading  dies,  taps,  reamers 
and  other  tools  to  be  subjected  to  torsional  (twisting) 
strains,  require  a  temperature  of  1950°  to  2150°  F., 
chisels,  some  classes  of  piercing  punches  and  other 


376  FORGE-PRACTICE. 

tools  that  are  to  receive  repeated  shocks  should  not 
be  heated  above  1800°  F.  and  in  case  of  very  severe 
usage  not  above  1750°  F. 

Cooling. — Pack-hardened  high-speed  steel  tools 
should  not  be  quenched  in  an  air  blast,  but  in  oil. 
For  many  tools  a  light  lard  oil  works  well,  but  for 
general  use  cotton-seed  oil,  or  a  commercial  hardening 
oil  is  best. 

The  pieces  should  be  worked  around  well  in  the 
bath  and  allowed  to  remain  until  cold.  The  cause  of 
failure  many  times  can  be  traced  to  insufficient  move- 
ment of  the  piece  in  the  bath.  This  is  especially  true 
of  large  tools,  milling-machine  cutters,  and  punch- 
press  blanking  dies  where  the  vapors  are  liable  to 
lodge  and  prevent  the  oil  reaching  the  essential  por- 
tions. 

As  the  melting  point  of  cast  iron  is  comparatively 
low  it  is  not  advisable  to  use  boxes  made  from  this 
material  when  pack  hardening  high-speed  steel  as 
they  are  liable  to  give  out  quickly.  The  most  satis- 
factory box  is  one  made  from  boiler  plate,  or  similar 
material. 

The  length  of  time  pieces  should  be  exposed  to  the 
temperatures  mentioned  varies  from  one  to  four 
hours  according  to  the  size  of  the  piece  and  the  use 
to  which  it  is  to  be  subjected.  Tools  hardened  by 
this  method  give  better  results  in  use  than  if  heated 
in  the  open  fire. 


TABLES. 


TABLE  I. 
CIRCUMFERENCES  AND  AREAS  OF  CIRCLES. 


Diam- 
eter. 

Circumfer- 
ence. 

Area. 

Diam- 
eter. 

Circumfer- 
ence. 

Area. 

i 

.7854 

.0490 

3 

9.4248 

7.0686 

.9817 

.0767 

9.8175 

7.6699 

f6 

.1781 

.1104 

^ 

IO  .  2IO 

8.2958 

•3744 

•I5°3 

1 

10  .603 

8  .9462 

|6 

.5708 

.1963 

1 

10  .996 

9  .621  1 

.7671 

.2485 

f 

11.388 

10.321 

I6 

•9635 

.3068 

f 

II  .781 

ii  .045 

% 

2.1598 

•3712 

| 

12.174 

H-793 

| 

2.3562 

•  4417 

4 

12  .  566 

12  .  566 

% 

2-5525 

.5184 

^ 

12-959 

I3.364 

% 

2.7489 

.6013 

!3.352 

I4.I86 

!%J 

.6902 

13-744 

15  .033 

I 

3.1416 

.7854 

I4.I37 

I5.904 

/l6 

3-3379 

.8866 

14.530 

16  .800 

| 

3-5343 

.9940 

\ 

14-923 

17.728 

/i<5 

3-7306 

•I075 

15-315 

18.665 

\ 

3.9270 

.  2272 

5 

15  .  708 

19-635 

/ie 

4-1233 

•3530 

16  .  101 

20  .629 

1 

4-3*97 

•  4849 

* 

i6.493 

21  .648 

4  .  5  160 

.6230 

I 

16.886 

22  .691 

* 

4.7124 

.7671 

\ 

17.279 

23.758 

/ie 

4.9087 

•9*75 

% 

17.671 

24.850 

r 

5  •  I05I 

2.0739 

| 

18  .064 

25.967 

5  •  3OI4 

2-2365 

% 

l8-457 

27.109 

i16 

5-4978 

2.4053 

6 

18.850 

28.274 

% 

5-6941 

2  .  5802 

£ 

19.242 

29.465 

1 

5-8905 

2  .7612 

i 

19-635 

3O  .680 

% 

6.0868 

2.9483 

1 

20  .028 

3L9I9 

2 

6.2832 

3.I4I6 

i 

20  .420 

33.183 

%> 

6-4795 

3-34io 

20.813 

34-472 

J 

6.6759 

3-5466 

1^ 

21  .  206 

35  •  785 

k 

6.8722 

3.7583 

{ 

21  .598 

37.122 

7.0686 

3-976i 

7 

21  .991 

38.485 

/fe 

7.2649 

4  .  2000 

22.384 

39-871 

1 

7-4613 

4.4301 

22.776 

41  .282 

Jfe 

7.6576 

4  .  6664 

j 

23.169 

42.718 

| 

7-8540 

4.9087 

23.562 

44-179 

% 

8.0503 

5  •  J572 

• 

23-955 

45.664 

f 

8.2467 

5.4119 

24-347 

47-J73 

% 

8.4430 

5.6727 

'  ' 

24.740 

48.707 

^ 

8.6394 

5-9396 

8 

25.I33 

50-265 

% 

8-8357 

6  .  2126 

| 

5r  -849 

£ 

9.0321 

6.4918 

£ 

25.918 

53-456 

% 

9.2284 

6.7771 

1 

26.311 

55-088 

379 


38o 


TABLES. 


TABLE  I— (Continued). 
CIRCUMFERENCES  AND  AREAS  OF  CIRCLES. 


Diam- 
eter. 

Circumfer- 
ence. 

Area. 

Diam- 
eter. 

Circumfer- 
ence. 

Area. 

8} 

26.704 

56.745 

i6i 

5I-05I 

207.39 

1 

27.096 

58.426 

\ 

51-836 

213.82 

f 

27.489 

60.132 

|^ 

52  .622 

220.35 

1 

27.882 

61.862 

17 

53.407 

226.98 

9 

28.274 

63-617 

i 

54.192 

233-71 

£ 

28.667 

65-397 

I 

54.978 

240'.  53 

| 

29  .060 

67.201 

f 

55-763 

247-45 

f 

29-452 

69  .  029 

18 

56.549 

254.47 

I 

29.845 

70.882 

1 

57-334 

261  .59 

f 

30-238 

72.760 

58.119 

268.80 

I 

30-631 

74  .662 

| 

58.905 

276  .  12 

1 

31-023 

76.589 

19 

59.690 

283.53 

10 

31  .416 

78,540 

60  .476 

291  .04 

f 

31  .809 

80.516 

\ 

61  .  261 

298.65 

I 

32  .201 

82.516 

f 

62  .046 

306.35 

f 

32.594 

84-541 

20 

62.832 

3I4.I6 

I 

32.987 

86.590 

i 

63-617 

322.06 

f 

33-379 

88.664 

\ 

64.403 

330.06 

f 

33-772 

90.763 

f 

65.188 

338.16 

£ 

34-165 

92.886 

21 

65-973 

346.36 

ii 

34.558 

95-033 

i 

66.759 

354-66 

34-95° 

97-205 

\ 

67.544 

363-05 

35-343 

99.402 

% 

68.330 

37J.54 

35.736 

101  .62 

22 

69.115 

380.13 

36.128 

103.87 

i 

69  .900 

388.82 

; 

36.521 

106  .  14 

\ 

70.686 

397.6i 

\ 

36.914 

108.43 

I 

71.471 

406.49 

' 

37.306 

110.75 

23 

72.257 

4I5-48 

12 

37-699 

113.10 

i 

73-042 

424.56 

J 

38.485 

117.86 

$ 

73-827 

433-74 

\ 

39.270 

122  .  72 

f 

74-613 

443  -OI 

^ 

40.055 

127.68 

24 

75-398 

452.39 

13 

40  .841 

132.73 

\ 

76.184 

461  .86 

I 

41  .626 

I37.89 

ft 

76.969 

47L44 

} 

42.412 

143  •I4 

| 

77-754 

481  .  ii 

f 

43-J97 

148.49 

25 

78.540 

490.87 

14 

43-982 

153-94 

i 

79-325 

500.74 

£ 

44-768 

I59-48 

i 

80  .  1  1  1 

510.71 

\ 

45-553 

165.13 

i 

80.896 

520.77 

| 

46.338 

170.87 

26 

81  .681 

530.93 

J5 

47.124 

176.71 

\ 

82.467 

54LI9 

| 

47-909 

182.65 

83-252 

55I-5S 

i 

48.695 

188.69 

| 

84-038 

562  .00 

i 

49  .480 

194.83 

27 

84.823 

572.56 

16 

50-265 

2OI  .06 

i 

85.608 

583-21 

TABLES. 


TABLE  I — (Continued). 
CIRCUMFERENCES  AND  AREAS  OF  CIRCLES. 


Diam- 
eter. 

Circumfer- 
ence. 

Area. 

Diam- 
eter. 

Circumfer- 
ence. 

Area. 

27l 

86.394 

593-96 

3g| 

121.737 

II79-3 

1 

87.179 

604.81 

39 

122  .  522 

1194  .6 

28 

87.965 

6I5-75 

123.308 

1210  .O 

i 

88.750 

626.80 

\ 

124.093 

1225.4 

\ 

89.535 

637-94 

t 

124.878 

1241  .0 

f 

90.32! 

649  .  18 

40 

125  .664 

1256  .6 

29 

91  .  106 

660  .  52 

^ 

126.449 

1272.4 

91  .892 

671  .96 

\ 

127.235 

1288.2 

\ 

92.677 

683.49 

f 

128  .020 

1304.2 

| 

93.462 

695  -J3 

128.805 

1320.3 

3° 

94.248 

706.86 

^ 

129.59! 

1336.4 

\ 

95-033 

718.69 

\ 

130.376 

1352.7 

ft 

95.819 

730.62 

f 

131  .l6l 

1369  .0 

f 

96  .604 

742.64 

42 

I3J-947 

1385-4 

31 

97  •  389 

754-77 

J 

132.732 

1402  .0 

98.175 

766.99 

1 

133-  5l8 

1418.6 

| 

98  .  960 

779-31 

1 

1435-4 

| 

99.746 

791-73 

43 

135.088 

1452.2 

32 

100.531 

804  .  25 

i 

135.874 

1469  .  i 

f 

101  .  316 

816.86 

\ 

136.659 

1486.2 

\ 

IO2  .  IO2 

829.58 

f 

137-445 

I503-3 

f 

102  .887 

842.39 

44 

138.230 

1520.5 

33 

103.673 

855-3° 

\ 

139-015 

1537-9 

J 

104.458 

868.31 

i 

139.801 

1555-3 

| 

'     105.243 

881  .41 

f 

140  .  586 

1572.8 

t 

106  .029 

894  .62 

45 

141-372 

I590-4 

34 

106  .814 

907.92 

i 

142.157 

1608.2 

^ 

107  .600 

921.32 

\ 

142.942 

1626.0 

| 

108  .385 

934.82 

f 

143.728 

i643-9 

^ 

109  .  170 

948.42 

46 

144-  5J3 

1661  .9 

35 

109  .  956 

962  .  ii 

i 

145.299 

1680  .0 

i 

no  .  741 

975-91 

146  .084 

1698.2 

^ 

111.527 

989.80 

| 

146.869 

1716.5 

f 

112  .312 

1003  .8 

47 

!47-655 

1734-9 

36 

113.097 

1017.9 

i 

148  .440 

1753.5 

113.883 

1032  .  i 

* 

149  .  226 

1772.1 

^ 

114.668 

1046.3 

f 

150  .on 

1790  .8 

f 

115-454 

1060  .  7 

48 

150.796 

1809.6 

37 

116  .  239 

1075.2 

i 

151-582 

1828.5 

^ 

117  .024 

1089.8 

t 

152-367 

1847  .  5 

| 

117  .810 

1104.5 

f 

I53-I53 

1866.5 

f 

118  .  596 

1119.2 

49 

I53-938 

1885.7 

38 

119.381 

1134-1 

1905.0 

i 

120  .  166 

1149.1 

\ 

I55-509 

1924.4 

* 

120  .951 

1164  .  2 

1 

156.294 

1943-9 

TABLES. 


TABLE  I — (Continued). 
CIRCUMFERENCES  AND  AREAS  OF  CIRCLES. 


Diam- 
eter. 

Circumfer- 
ence. 

Area. 

Diam- 
eter. 

Circumfer- 
ence. 

Area. 

5° 

157  .080 

I963-5 

62* 

196.350 

3068  .0 

i 

157-86*5 

1983.2 

63 

197.920 

3117.2 

i 

158  .650 

2003  .0 

\ 

199.491 

3166.9 

1 

I59-436 

2022  .8 

64 

201  .062 

3217-0 

51 

l6o  .  221 

2042  .8 

* 

202  .633 

3267.5 

i 

161  .007 

2062  .9 

65 

204  .  2O4 

3318.3 

* 

161  .  792 

2083.1 

\ 

205.774 

3369.6 

I 

162.577 

2103.3 

66 

207.345 

3421  .2 

S2 

163-363 

2123.7 

\ 

208  .916 

3473-2 

i 

164  .  148 

2144.2 

67 

210  .487 

3525-7 

i 

164.934 

2164.8 

\ 

212  .058 

3578.5 

I 

165.719 

2185.4 

68 

213  .628 

3631-7 

53 

166.504 

2206  .  2 

\ 

215  .  199 

3685.3 

i 

167  .  290 

2227  .O 

69 

216  .  770 

3739-3 

i 

168  .075 

2248  .O 

\ 

218  .341 

3793-7 

i 

168.861 

2269  .  I 

70 

219  .911 

3848.5 

54 

169  .646 

2290  .  2 

\ 

221  .482 

3903.6 

i 

170.431 

23II.5 

71 

223.053 

3959-2 

i 

171.217 

2332.8 

\ 

224  .624 

4015.2 

! 

172  .002 

2354.3 

72 

226  .  195 

4071.5 

55 

172.788 

2375-8 

\ 

227.765 

4128.2 

i 

173-573 

2397-5 

73 

229.336 

4185.4 

i 

I74.358 

2419.2 

\ 

230.907 

4242.9 

I 

I75-I44 

2441  .1 

74 

232.478 

4300.8 

56 

175.929 

2463  .0 

\ 

234.049 

4359-2 

i 

176.715 

2485.0 

75 

235.619 

4417-9 

i 

177.500 

-2507.2 

\ 

237.190 

4477-0 

f 

178.285 

2529.4 

76 

238.761 

4536.5 

57 

179.071 

2551-8 

i 

240.332 

4596.3 

i 

179.856 

2574-2 

77 

241  .903 

4656  .6 

i 

180.642 

2596.7 

\ 

243-473 

47I7-3 

181  .427 

2619  .4 

78 

245.044 

4778.4 

58 

l82  .212 

2642  .  I 

\ 

246  .615 

4839-8 

i 

l82  .998 

2664  .9 

79 

248.186 

4901  .7 

183.783 

2687.8 

\ 

249-757 

4963.9 

I 

184  .  569 

2710.9 

80 

25J-327 

5026.5 

59 

185.354 

2734-0 

* 

252.898 

5089  .6 

i 

186.139 

2757.2 

81 

254-469 

5i53.o 

186  .925 

2780.5 

\ 

256  .040 

5216.8 

| 

187.710 

2803.9 

82 

257  .611 

5281  .0 

60 

188.496 

2827.4 

\ 

259  .  181 

5345-6 

I 

190  .066 

2874.8 

83 

260  .  752 

5410.6 

61 

191.637 

2922.5 

\ 

262.323 

5476.0 

\ 

193  .  208 

2970  .6 

84 

263.894 

5541-8 

62 

194.779 

3019.1 

* 

265.465 

5607.9 

TABLES. 


TABLE  I— (Continued). 
CIRCUMFERENCES  AND  AREAS  OF  CIRCLES. 


Diam- 
eter. 

Circumfer- 
ence. 

Area. 

Diam- 
eter. 

Circumfer- 
ence. 

Area. 

85 

267.035 

5674.5 

93 

292  .  168 

6792.9 

£ 

268.606 

5741-5 

\ 

293-739 

6866.1 

86 

270.177 

5808.8 

94 

295.310 

6939.8 

i 

271  .748 

5876.5 

i 

296.881 

7013.8 

87, 

273-3!9 

5944-7 

95 

298.451 

7088.2 

* 

274.889 

6013  .  2 

i 

300  .022 

7163.0 

88 

276  .460 

6082.1 

96 

3OI-593 

7238.2 

1 

278.031 

6151  .4 

\ 

3°3-l64 

73I3-8 

89 

279.602 

6221  .  I 

97 

3°4-734 

7389.8 

i 

281.173 

6291  .2 

\ 

306.305 

7466.2 

90 

282.743 

6361.7 

98 

307.876 

7543-0 

* 

284.314 

6432.6 

i 

309.447 

7620  ,  i 

91 

285.885 

6503-9 

99 

311  .018 

7697.7 

* 

287.456 

6575-5 

312.588 

777.*  6 

92 

289  .027 

6647.6 

IOO 

3J4-I59 

7854-0 

i 

290.597 

6720  .  I 

TABLES. 


TABLE  II. 

TEMPERATURES  TO  WHICH  HARDENED  TOOLS  SHOULD  BE  HEATED 
TO  PROPERLY  "DRAW  THE  TEMPER,"  TOGETHER  WITH 
THE  COLORS  OF  SCALE  APPEARING  ON  A  POLISHED-STEEL 
SURFACE  AT  THOSE  TEMPERATURES,  AND  OTHER  MEANS 
OF  DETECTING  PROPER  HEATING. 


Kind  of  Tool. 

Temper- 
ature, 
Fahr. 

Color  of 
Scale. 

Action  of 
File. 

Other  Indi- 
cations. 

Scrapers    for    ordi- 

200° 

Water  dries 

nary  use. 

quickly. 

Burnishers. 

Very    pale 

Can  hardly 

Lard-oil 

Light    turning    and 
finishing  tools. 

430° 

yellow. 

be    made 
to  catch. 

smokes 
slightly. 

Engraving-tools. 
Lathe-  tools. 

Can      be 
made     to 

Milling-cutters. 

460° 

Straw  -  yel- 

catch 

Lathe-  and   planer- 

low. 

with    dif- 

tools    for     heavy 

ficulty. 

work. 

Taps. 

Dies  for  screw-cut  'g. 

Reamers. 

Punches. 

Dies. 

Flat  drills. 

Wood-  working  tools. 

500° 

Brown-yel- 

Plane-irons. 

low. 

Wood-chisels. 

Wood-turning  tools. 

Twist  drills. 

Sledges. 

Bl'ksmiths'    ham'rs 

Cold-chisels  for  very 

530° 

Light  pur- 

Scratches. 

light  work. 

ple. 

Axes. 

550° 

Dark  pur- 

Cold-chisels for    or- 
dinary use. 

ple. 
Blue,  ting'c 

slightly 
with  red. 

Stone-cutting  chisels 

Files     with 

Carving-knives. 

great  dif- 

Screw-drivers. 

ficulty. 

Saws. 

Springs. 

580° 

Blue. 

Files     with 

Lar  d-oi  1 

610° 

Pale  blue. 

difficulty 

burns  or 

630° 

Greenish 

flashes. 

blue. 

TABLES. 


385 


TABLE  III. 
DECIMAL  EQUIVALENTS  OF  FRACTIONS  OF  ONE  INCH. 


From  Kent's  Mechanical  Engineer's  Pocket-book. 


1/64 

.015625 

33/64 

1/32 

•03125 

J7/32 

3/64 

.046875 

35/64 

1/16 

.0625 

9/1  6 

5/64 

.078125 

37/64 

3/32 

•09375 

J9/32 

7/64 

•I09375 

39/64 

1/8 

.125 

5/8 

9/64 

.  140625 

41/64 

5/32 

•I5625 

21/32 

11/64 

.171875 

43/64 

3/i6 

.i875 

11/16 

13/64 

.203125 

45/64 

7/32 

-21875 

'23/32 

15/64 

•234375 

47/64 

i/4 

•25 

3/4 

17/64 

.265625 

49/64 

9/32 

.28125 

25/32 

19/64 

.296875 

5J/64 

5/i6 

•3125 

13/16 

21/64 

•328125 

53/64 

11/33 

•34375 

27/32 

23/64 

•359375 

55/64 

3/8 

•375 

7/8 

25/64 

.390625 

57/64 

13/32 

.40625 

29/32 

27/64 

.421875 

59/64 

7/16 

•4375 

I5A6 

29/64 

•453125 

61/64 

IS/32 

•46875 

31/32 

31/64 

.484375 

63/64 

1/2 

•5° 

I 

•5*5625 

•53*25 

•546875 

•5625 

•578125 

•59375 

•609375 

.625 

.640625 

.65625 

.671875 

.6875 

•703125 

•71875 

•734375 

•75 

.765625 

.78125 

.796875 

.8125 

.828125 

•84375 

•859375 

.875 

.890625 

.90625 

.921875 

•9375 
•953125 
.96875 
•984375 


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(From  J 


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EIGHTS 
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COURSE  OF  EXERCISES  IN  FORGE  WORK. 

What  is  suggested  as  a  standard  course  of  exer- 
cises is  given  below. 

A  short  talk  should  first  be  given  covering  the 
calculation  of  stock  for  simple  bent  work,  rings, 
links,  eyes,  etc. 

The  starting  of  the  fire  and  fitting  of  tongs  is 
then  explained. 

Exercise  i.  Stock  ^"Xj"x6"  is  drawn  out  to  \" 
round,  and  this  round  stock  is  used  to  make 
the  two  following  pieces  of  work. 

Exercise  2.  Fig.  338.    Eye  Bend. 

Exercise  3.  Fig.  339.     Double  Eye  Bend. 

Exercise  4.  Fig.  341.    Twisted  Gate  Hook. 

Exercise  5.  Fig.  342.     Square  Point  and  Eye  Bend. 

Exercise  6.  Fig.  377.  Twisted  Scriber.  Before  giv- 
ing this  exercise  a  short  talk  should  be  given 
on  the  effect  of  high  heats  on  tool  steel.  The 
scriber  should  be  forged  from  an  old  file  in 
order  to  give  practice  in  the  drawing  out  of. 
tool  steel.  The  scriber  is  tempered  later  in  the 
course. 

Exercise  7.  Fig.  342.    Weldless  Ring. 

Exercise  8.  Fig.  355.     Chain  Hook. 

Exercise  9.  Fig.  351.    Bracket  with  Forged  Corner. 

387 


388  FORGE-PRACTICE. 

Exercise  10.  Practice  Weld.  This  should  be  a  sort 
of  a  faggot  weld  made  by  doubling  over  the 
end  of  a  piece  of  scrap,  the  object  being  simply 
to  determine  the  welding  heat. 

Exercise  n.  Fig.  357.    Chain  of  Three  Links. 

Exercise  12.  Fig.  348.     Flat  Lap  Weld. 

Exercise  13.  Fig.  349.    Angle  Weld. 

Exercise  14.  Fig.  347.  Welded  Ring.  This  and  the 
hook  made  in  Ex.  9  should  each  be  joined  to 
the  chain  by  extra  links,  making  a  chain  of 
five  links  with  the  hook  on  one  end  and  the 
ring  on  the  other. 

Exercise  15.  Fig.  373.  Welded  Rings  shrunk  to- 
gether. 

Exercise  16.  Fig.  358.  Planer  Bolt,  make  welded 
head. 

Exercise  17..  Fig.  352.  Hexagonal  Head  Bolt, 
upset  head. 

Exercise  18.  Fig.    354.      Ladle. 

Exercise  19.  Fig.    367.      Taper  Machine  Key. 

Exercise  20.  Fig.    368.      Lever  Arm. 

Exercise  2 1 .  Figs.  370,  371,  or  3  7 2 .     Tongs. 

Exercise  22.  Hardening  Tool  Steel.  The  stddent 
should  be  given  an  old  file  or  piece  of  scrap 
tool  steel  to  determine  the  proper  hardening 
heat.  This  is  done  by  drawing  out  the  steel 
to  about  J"  square  and  hardening  the  end, 
which  is  then  snapped  off  and  the  condition 
of  the  steel  determined  from  the  fracture. 
This  should  be  repeated  until  the  hardening 
heat  can  be  hit  upon  every  time. 

Exercise  23.  Fig.  313.    Cold  Chisel. 


COURSE  OF  EXERCISES  IN  FORGE  WORK.  389 

Exercise  24.    Fig.  380.     Center  Punch. 

Exercise  25.    Fig.  397.     Cape  Chisel. 

Exercise  26.    Figs.  382  or  383.     Thread  Tool. 

Exercise  27.   Fig.  384.     Round  Nose  Tool. 

Exercise  28.   Fig.  381.     Side  Tool. 

Exercise  29.    Fig.  387.     Boring  Tool. 

Exercise  30.    Fig.  385.     Diamond  Point. 

Exercise  31.    Figs.  393,  394,  395,  396,  or  399.      Hot 

Chisel,    Cold   Chisel,    Set   Hammer,  Flatter  or 

Pattern-maker's  Hammer. 
Exercise  32.    Fig.  400.     Spring. 
Exercise  33.   Fig.  375.     Brazed  Ring. 

Many  students  will  be  able  to  cover  much  more 
ground  than  outlined  above,  and  for  such  cases 
additional  drawings  are  given.  These  additional 
exercises  may  be  interpolated  where  the  instructor 
sees  fit. 

Additional  drawings  are  also  given  in  order  that  the 
course  may  be  varied  somewhat  from  term  to  term. 

No  more  than  three  pieces  of  stock  should  ever 
be  allowed  for  any  one  exercise,  and  as  a  general 
rule  the  student  should  do  the  work  with  one. 
When  more  than  one  piece  is  used  the  work  should 
be  graded  down  accordingly. 

Talks  should  be  given  on  Brazing,  Case  Hard- 
ening, Metallurgy  of  Bessemer,  Open  Hearth,  and 
Crucible  Steels  and  Wrought  Iron. 

Considerable  work  should  also  be  done  in  making 
sketches  and  stock  calculations  for  large  machine 
forgings,  the  sketches  to  show  the  different  steps 
in  the  forging  process. 


390  FORGE-PRACTICE. 

When  a  steam  or  power  hammer  is  available  old 
hammers,  tools,  etc.,  may  be  drawn  out  into  bar 
stock  for  center  punches,  small  chisels,  etc. 

The  tongs  shown  in  the  drawings  may  be  made 
to  good  advantage  under  a  steam  or  power 
hammer. 


COURSE   OF    EXERCISES   IN   FORGE    WORK.  391 


1      Fig.  341 


TWISTED  GATE  HOOK 


392 


FORGE-PRACTICE. 


COURSE    OF    EXERCISES    IN   FORGE    WORK.  393 


m          oo 

5       S 


I: 


* 


394 


rORGE-PRACTICE. 


Calculate  dimensions  of  head 


2 

* 

v 

j 

k                    4" 

x  4  HEX.  HEAD  BOLT 


Fig.  352 


OPEN  WRENCH  Fig.  353 


COURSE   OF   EXERCISES   IN   FORGE    WORK.  395 


396 


FORGE-PRACTICE. 


Finish  all  over 


PLANER   BOLT  Fig.  358 


PLANZR  STRAP  No.  1 


-  359 


Length  as  required 


PLANER  STRAP  No.  2 
Fig.  360 


COURSE    OF    EXERCISES    IN    FORGE    WORK.  397 


398 


FORGE-PRACTICE. 


COURSE    OF    EXERCISES    IN    FORGE    WORK.  399 


Fig.  366 
•C"  CLAMP 


TAPER  KEY   Finish  all  over 
Fig.  367 


Fig.  369 
LEVER  &  HANDLE 


-%— >> 


N] 

2 


4oo 


FORGE -PRACTICE. 


I  I 


COURSE    OF    EXERCISES   IN   FORGE    WORK.  4-OI 


WELDED  RINGS  SHRUNK  TOGETHER    j< — % 


Fig.  373 


Fig.  375 


BUTTON  SLICK 


T 


*-%  Washer  /f 

-Braze  M  Gas  pipe 


Fig.  376 


BRAZED  FLANGE 


4O2 


FORGE-PRACTICE. 


0 


d  W 

C/5        .  I  * 


3> 

li 


COURSE    OF   EXERCISES   IN   FORGE    WORK.  403 


RIGHT  HAND  SIDE 


THREAD  TOOL  No.1 


-5-8  on  new  Tools- 


Fig.  383 


THREAD  TOOL  No. 2 


ROUND   NOSE  TOOL 


404 


FORGE-PRACTICE 


Fig.  385 


Fig.  386 


Fig. 387 


For  internal  threading 
make  nose  of  tool  like  this 


sVon  new  Tools 


CUTTING  OFF  TOOL 


Fig.  388 

i   i   K" 


COURSE    OF    EXERCISES   IN   FORGE    WORK.  405 


;  FLAT  SCRAPER  | 

(May  be  made  from  old  file  )  Fl£-  39° 


HALF  ROUND  SCRAPER       Fig.  391 
(May  be  made  from  old  half  round  file  as  shown  by  dotted  lines ) 


Fig.  392 


406 


FORGE-PRACTICE. 


Fig.  393     BLACKSMITH'S  HOT  CHISEL 

BLACKSMITH'S  COLD  CHISEL 

Fig.  394    Make  same  way  but  shape  end  as  shown 
by  dotted  line. 


Fig.  395 


FLATTER 


Fi#.  396 


COURSE    OF    EXERCISES   IN   FORGE    WORK.  407 


Fig.  397 


-About-8- 


CAPE  CHISEL 


ROUND  NOSE  OR  CENTERING  CHISEL 


PATTERN  MAKER'S  HAMMER 
Fig.  399 


Give  Spring  Temper 
all  over. 


INDEX, 


Alloy  steels,  202,  203. 
Animal  charcoal,  335. 
Annealing,  in  general,  266. 

"        ,  box,  269. 

before  hardening,  374. 
copper  and  brass,  193. 

"          high-speed  steel,  364. 

"        ,  overheating  when,  268. 

' '        ,  prolonged  heats  in,  268. 

"        ,  quick,  368. 

"        ,  temperatures  for,  266. 

"        ,  undesirable  results  when,  271, 

"        ,  water,  273. 

' '          without  discoloring,  367. 
Anvil,  description  of,  6. 

Baths,  cooling,  226. 

' '       for  tempering,  247. 
Bending,  59. 

"         cast-iron,  194. 
"         duplicate  work,  146. 
"         pipe,  188. 
Bessemer  converter,  two  types  of,  200. 

"        steel,  200,  201. 
Bolts,  general  dimensions  of,  77. 
' '    ,  cupping-tool  for,  78. 
' '    ,  heading-tool  for,  78. 
"    ,  making  of,  77. 
'*    ,  upset-head,  79. 
"    ,  welded-head,  80. 
Bone  for  case  hardening,  335. 
Borax  used  as  a  flux,  21. 
Boss  on  flange,  forging  of,  144. 

409 


410  INDEX 

Boss  on  lever,  forging  of,  in. 
Bowls,  making  of,  88. 
Brace,  or  bracket,  welded,  119. 
Brazing,  flux  used,  188. 

"      ,  methods  of,  185. 

"     ,  process  of,  184. 

"     ,  spelter  for,  1 86. 
Brine-bath,  233. 
Butt-weld,  34. 

Calculation  of  stock,  see  Stock  calculation. 
Cape-chisel,  forging  and  tempering  of,  161. 
Carbon  percentages  for  various  tools,  206. 
Case  hardening,  332. 

"          "         ,  animal-charcoal  used  in,  335. 

'  *          ' '         ,  barium-carbonate  used  in,  336. 

"          "  bath  for  color  work,  345. 

"          "         ,  boxes  for  use  in,  337. 

1 '          '  *         ,  carburizers  for  use  in,  334. 

"          "         ,  charred-bone  for  use  in,  335. 

"          "         ,  charred-leather  for  use  in,  336. 

"          "         ,  cyanide  of  potassium  for  use  in,  333,  357. 

* '          ' '         ,  deep  penetration  in,  348. 

"          "  with  gas  as  carburizer,  356. 

"          "         ,  examples  of,  347. 

"          "  for  strength,  354. 

"  large  nuts,  348. 

,  local,  351- 

' '          ' '         ,  mixtures  used  in,  337. 
"          * '         ,  oil  bath  for,  346. 
' '  ' '  small  pieces,  340. 

Cast-iron,  bending  of,  194. 
Causes  of  trouble  when  hardening,  322. 
Chain  making,  30. 

"     ,  stock  required  to  make  link,  48. 
"       stop,  forging  of,  88. 

Changes  in  length  of  steel,  when  hardened,  262. 
Chisels,  blacksmiths,  hot  and  cold,  6. 

"  "          ,  forging  and  tempering,  180. 

"  "          ,  grinding,  8. 

"    ,  or  cutters  for  steam-hammers,  123. 
Chrome-vanadium  steel,  203. 


INDEX  411 


Coal,  requirements  of  forge,  2. 
Coke  fire,  214,  369. 

Cold-chisels,  descriptions  of  blacksmiths,  7. 
"         "    ,  making  of,  159. 
"         "      hardening  and  tempering,  160,  276. 
Cold-dropping  dies,  hardening,  316. 
Cooling  with  streams  of  water,  231. 
Cones,  sentinel,  223. 
Connecting-rod,  ,  forging  of  forked  end,  104. 

"  "     with  steam-hammer,  1380 

"  "     ,  stock  calculations  for,  93. 

Copper,  annealing  of,  193. 
Copper-pipe,  bending,  192. 
Course  of  exercises  in  forge  work,  387. 
Crank-shaft,  calculations  of  stock  required,  91, 
"         "    ,  forging  with  steam-hammer,  135. 

"      of  single-throw,  90,  97. 
"        "          "      "  double-throw,  99. 
"         "  "      "  triple-throw,  101. 

Crucible  tool-steel,  carbon  percentages,  206. 
Cupping-tools,  for  bolts,  78. 
Cutting-block,  description  of,  10. 
Cutting  stock,  methods,  of,  9. 
Cyanide  of  potassium  for  case-hardening,  333,  357. 

Decalescence  point,  258. 
Direct-flame  furnace,  210. 
Disintegration,  326. 
Drop-forging  dies,  description  of,  154. 

"     )  hardening,  315. 
"         "       "       for  hot  forming,  157. 
"         "       eye-bolts,  155. 
"         "       with  steam-hammer,  158. 
Duplicate  bending  with  block,  147. 

11    Jig,  152. 
"        work,  146. 

Effect  of  high  heats  on  steel,  196. 

Electric  furnaces,  371. 

Exact  temperatures  when  hardening,  239. 

Examples  of  hardening,  275. 

Eye,  bending  of,  64. 


412  INDEX 

Eye,  weldless,  making  of,  from  flat  stock,  1090 
Eye-bolt,  drop-forging  of,  155. 

File  finish,  allowance  for,  95. 
Fire,  banking  of,  4. 
"  ,  building  of,  2. 
"    ,  description  of  good,  3. 
"  ,  oxidizing,  5. 

Flange,  with  boss,  forging  of,  143. 
Flux  for  brazing,  188. 

"    ,  use  of,  in  welding,  20. 
Forge,  description  of,  i. 
Fork,  welded,  119. 
Forked  ends,  forging  of,  102,  107. 
Fullers,  description  of,  15. 

"      ,  forging  of,  182. 
Fuel  for  use  in  heating  furnaces,  213. 
Furnaces,  heating,  209. 
"        ,  coke,  214. 
"        ,  .direct  flame,  210. 
"        ,  muffle,  209. 
"        ,  preheating,  370. 
"        ,  bottom-fired,  211. 
"        ,  semi-muffle,  209. 
"        ,  top-fired,  212. 

Gate-hook,  making  of,  68. 

Hammers,  description  of,  10. 

"       ,  ball-pene,  178. 

"       ,  forging  and  tempering  of,  174,, 

"       ,  riveting,  176. 

"       ,  sledge,  179. 
Hardening,  239. 

and  tempering,  256. 

"        ,  brine-bath  used  in,  233. 

"        ,  burnishing  dies,  287. 

carbon  tool-steel,  239,  332. 

"        ,  causes  of  trouble  when,  322. 

"          cold-chisels,  160,  276. 

"  cutting,  or  dinking-dies,  290. 

"          curling-dies,  291. 


INDEX,  413 


Hardening  dies,  279. 

"          dies  with  thin  sections,  283. 
"          draw-broaches,  306. 

drop-forging  dies,  315. 
forming  and  bending  dies,  290. 
"        ,  heats  for,  239. 
"          high-speed  steel,  369. 

large  rings,  307. 
"         ,  magnet  used  in,  258. 
"          milling-cutters,  296. 

piercing-punches,  275. 
punch-press  dies,  279. 
"  redrawing  dies,  284. 

"          rivet  sets,  307. 

spring- threading  dies,  310. 
taps,  291. 
thin  cutters,  304. 
threading  dies,  295,  310. 
with  steam,  238. 
with  vapor,  238. 
with  water-bath,  235. 
with  water  sprays,  236,  238. 
Hardie,  description  of,  7. 

"      ,  forging  of,  180. 
Heading-tool  for  bolts,  78. 
Heating-furnaces,  209. 
Heat-recording  instruments,  219, 
Heat-treatment  of  steel,  194. 
Hook,  chain,  71. 
"    ,  gate,  68. 
"    ,  grab,  70. 
"     ,  hoist,  75. 
11       with  welded  eye,  74. 
Hot-chisel,  description  of,  7. 

"     "     ,  forging  of,  180. 
High-speed  steel,  forging,  361. 

"       "        "      tools,  forms  of,  363. 


Jump-weld,  35. 

Knuckles,  forging  various  kinds  of,  102. 


414  INDEX 

Ladles,  making  of,  86. 

Ladle  shank,  forging  of  foundry,  114. 

Laps  in  steel,  325. 

Lathe  tools  in  general,,  162. 

"       "     ,  boring,  167. 

"       "     ,  centering,  172. 

"       "     ,  cutting-off,  164. 

"       "     ,  diamond-point,  168. 
'    ,  finishing,  172. 

"       "     ,  internal  thread,  168. 

"       "    ,  round-nose,  163. 

"       "     ,  side,  170. 

"       "     ,  thread,  163. 
Lead-bath  for  heating  steel,  216,  372, 
Light  in  the  hardening-room,  207. 
Long  continued  heats,  effects  of,  324, 

Machine-steel,  201. 
Magnet  used  in  hardening,  258. 
Molders  trowel,  forging  of,  117. 
Muffle-furnace,  209. 

Nickel-steel,  202. 
Nickel-chrome-steel,  203. 

Oil-tempering  furnace,  247. 
Open-hearth  steel,  200. 
Over  annealing,  323. 
Over  heating,  324. 

"         "      ,  when  hardening,  240. 
Oxide,  formation  of,  on  iron,  5. 
Oxidizing  fire,  5. 
Oxygen,  effect  of  on  iron  when  heating,  5* 

Pack-hardening,  328. 

gauges,  331. 
high-speed  steel,  375. 
,  temperatures  when,  330= 
"         "          ,  time  exposure  when,  330. 
Pipe-bending  in  general,  188. 
"         "      ,  copper,  192. 
"         "      ,  different  methods,  190. 


INDEX 

Pipe-bending  with  jigs,  191,  193. 

Piping,  325. 

Planer-tools,  see  Lathe-tools. 

Point,  meaning  of,  200. 

Pointing,  precautions  necessary,  52. 

Pre-heating  high-speed  steel,  370. 

furnaces,  370. 

Punch,  for  steam-hammer,  141. 
Punching,  methods  of,  and  tools  used,  58. 

"        ,  tools  for  duplicate,  142. 
Pyrometer,  221. 

"        ,  calibrating  of,  222,  224. 

Quick  annealing,  368. 
Quick  case-hardening,  333. 

Recalescence  point,  259. 

Redrawing  dies,  hardening,  284. 

Retarding  the  cooling  of  light  sections,  240,  283. 

Reworking  drop-forging  dies,  322. 

Rings,  amount  of  stock  required,  46. 

"    ,  bending  up,  63. 

"    ,  forging  under  steam-hammer,  139. 

"    ,  welding  of  flat  stock,  32. 

round  stock,  29. 
washer,  33. 

"    ,  weldless  making  of,  no. 
Round-nosed  chisels,  168. 

Salt  baths,  373. 
Sand,  uses  of,  as  flux,  21. 
Scarfing  for  weld,  object  of,  23. 
Seams  in  steel,  325. 
Semi-muffle  furnaces,  209. 
Sentinel  cones,  222. 
Set-hammer,  description  of,  14. 

"         "      ,  making  of,  181. 
Shaper-tools,  see  Lathe-tools. 
Shore  sceroscope,  243. 
Shrinking,  process  of,  183. 
Sledges,  description  of,  n. 
"       ,  hardening  and  tempering,  179. 


415 


416  INDEX 

Socket  wrench,  forging  of,  106. 

Spelter  for  brazing,  186. 

Split  work,  shaping  from  thin  stock,  107. 

Springing,  260. 

Spring-steel,  welding  of,  35. 

Spring- tempering,  310. 

Square  corner,  forging  of,  60. 

Steam-hammer,  description  of,  120. 

"        ,  cutting  work  under,  127. 
"        ,  forging  taper  work  with,  130. 
"        ,  general  notes  on,  126. 
"        ,  tongs  for,  121. 
"        ,  tools  and  swages  for,  129. 
"        ,  tools  for  cutting  work  with,  123. 
Steel,  199. 

"      for  milling  cutters,  299. 
"      for  taps,  293. 
"        "  various  tools,  205. 
Stock  calculations,  in  general,  41. 
"  "          ,  for  circles,  46. 

"  "  "  connecting-rod,  92. 

"  "  "  curves,  44. 

"       •     "  "  links,  etc.,  48. 

"   simple  bends,  44. 

"  "  "   single-throw  crank,  91. 

"  "  "   weldless  ring,  no. 

Straightening  pieces  that  are  sprung,  261. 

Table  of  temperatures  for  forging  and  hardening,  332, 

Tables,  379-385- 

Taper  work  with  steam-hammer ,^130,  145. 

Tempering,  246. 

Temper  color  chart,  247. 

Temperature  of  bath,  241. 

Temperature  scales,  253. 

Tempering  furnace,  247. 

"          on  hot  plate,  250. 

"          machine,  250. 

"          in  sand,  252. 
Testing  hardened  steel,  242. 
Tongs,  description  of,  12. 
"     ,  fitting  of,  13. 


INDEX  417 


Tongs  for  round  stock,  forging  of,  83. 
'    steam-hammer  work,  121. 

"     ,  forging  bolt,  84. 

"     ,      "         of  light  hand,  81. 

"     ,      "         "pick-up,  84. 

"     ,      "         ",  with  welded  handles,  84. 

"     ,      "        with  steam-hammer,  133. 
Tool  forging  in  general,  160. 
Tool-steel,  204. 
Toughening,  255. 

Troubles  experienced  when  hardening  mills,  305. 
Trowel,  forging  of  moulders,  117. 
Truing- up  work,  54. 

"  "     ,  under  steam-hammer,  133. 

Tuyere,  use,  and  description  of,  i. 
Twisting  for  ornamental  work,  66. 
"        gate-hook,  70. 

Underfired  furnace,  211. 
Undesirable  results  when  annealing,  271. 
Uniform  heating,  240,  324. 
Upsetting,  definition  and  methods  of,  55. 
tool-steel,  327. 

Value  of  experiments,  263. 

Water-annealing,  273. 
"     baths,  233,  235. 
"     sprays,  238. 
Weight  of  bar  iron  and  steel,  386. 

"  forgings,  calculations  of,  94. 
Weld,  angle,  flat  stock,  37. 
"    ,  butt,  34. 
'    ,  chain,  19,  30. 
"    ,  faggot,  or  pile,  22. 
"    ,  flat-lap-,  24. 
"    ,  fork,  119. 
' '    ,  iron  to  steel,  36. 
"    Jump,  35. 
"    ,  ring,  flat  stock,  32. 
"    ,     "  ,  round  stock,  29. 
"    ,  round  lap-,  28. 


41 8  INDEX 

Weld,  split,  for  heavy  work,  36. 
"    ,  split,  for  light  work,  35. 
"    ,  spring-steel,  35. 
"     ,  "T",  flat  stock,  38. 
"    ,  "T",  round  stock,  39. 
"    ,  washer,  or  flat  ring,  33. 
Welding  in  general,  17. 

"      ,  allowance  of  stock  for,  26, 
"      ,  scarfing  for,  23. 
"        spring-steel,  35,  40. 
"        tool-steel,  39. 
' '      ,  uses  of  flux  in,  20. 
Wood-charcoal  as  a  carburizer,  336. 
Wrench  for  twisting  crank-shaft,  100. 
"      ,  forging  of  open-end,  105. 
"      ,       "      "  socket,  106. 


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